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1. What Determines the Boundaries of H2O Maser Emission in an X-ray Illuminated Gas Disk ?

Author

Kuo, C. Y., Gao, F., Braatz, J. A., Pesce, D. W., Humphreys, E. M. L., Reid, M. J., Impellizzeri, C. M. V., Henkel, C., Wagner, J., and Wu, C. E.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

High precision mapping of H2O megamaser emission from active galaxies has revealed more than a dozen Keplerian H2O maser disks, which enable a ~4% uncertainty estimate of the Hubble constant as well as providing accurate masses for the central black holes. These disks often have well-defined inner and outer boundaries of maser emission on sub-parsec scales. In order to better understand the physical conditions that determine the inner and outer radii of a maser disk, we examine the distributions of gas density and X-ray heating rate in a warped molecular disk described by a power-law surface density profile. For a suitable choice of the disk mass, we find that the outer radius R_out of the maser disk predicted from our model can match the observed value, with R_out mainly determined by the maximum heating rate or the minimum density for efficient maser action, depending on the combination of the Eddington ratio, black hole mass, and disk mass. Our analysis also indicates that the inner radius for maser action is comparable to the dust sublimation radius, suggesting that dust may play a role in determining the inner radius of a maser disk. Finally, our model predicts that H2O gigamaser disks could exist at the centers of high-z quasars, with disk sizes of >~ 10-30 pc., Comment: Accepted by MNRAS, 17 pages, 8 figures, 2 tables

Published
2023

2. SYMBA: An end-to-end VLBI synthetic data generation pipeline

Author

Roelofs, F., Janssen, M., Natarajan, I., Deane, R., Davelaar, J., Olivares, H., Porth, O., Paine, S. N., Bouman, K. L., Tilanus, R. P. J., van Bemmel, I. M., Falcke, H., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A., Ball, D., Baloković, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D., Carlstrom, J. E., Chael, A., Chan, C., Chatterjee, S., Chatterjee, K., Chen, M., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., De Laurentis, M., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gómez, J. L., Galison, P., Gammie, C. F., García, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J., Kino, M., Koay, J. Yi, Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C., Lauer, T. R., Lee, S., Li, Y., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R., MacDonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Martí-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Müller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Neri, R., Ni, C., Noutsos, A., Okino, H., Ortiz-León, G. N., Oyama, T., Özel, F., Palumbo, D. C. M., Patel, N., Pen, U., Pesce, D. W., Piétu, V., Plambeck, R., PopStefanija, A., Prather, B., Preciado-López, J. A., Psaltis, D., Pu, H., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sánchez, S., Sánchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. Peter, Schuster, K., Shao, L., Shen, Z., Small, D., Sohn, B. Won, SooHoo, J., Tazaki, F., Tiede, P., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Wardle, J., Ward-Thompson, D., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y., Zensus, J. A., Zhao, G., Zhao, S., and Zhu, Z.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a comparison with observational data. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a mm VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects. Based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M87, we performed case studies to assess the attainable image quality with the current and future EHT array for different weather conditions. The results show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of the input models can be recovered robustly after performing calibration steps. With the planned addition of new stations to the EHT array, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images., Comment: 20 pages, 15 figures, accepted for publication in A&A

Published
2020
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3. The Megamaser Cosmology Project. XIII. Combined Hubble constant constraints

Author

Pesce, D. W., Braatz, J. A., Reid, M. J., Riess, A. G., Scolnic, D., Condon, J. J., Gao, F., Henkel, C., Impellizzeri, C. M. V., Kuo, C. Y., and Lo, K. Y.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We present a measurement of the Hubble constant made using geometric distance measurements to megamaser-hosting galaxies. We have applied an improved approach for fitting maser data and obtained better distance estimates for four galaxies previously published by the Megamaser Cosmology Project: UGC 3789, NGC 6264, NGC 6323, and NGC 5765b. Combining these updated distance measurements with those for the maser galaxies CGCG 074-064 and NGC 4258, and assuming a fixed velocity uncertainty of 250 km s$^{-1}$ associated with peculiar motions, we constrain the Hubble constant to be $H_0 = 73.9 \pm 3.0$ km s$^{-1}$ Mpc$^{-1}$ independent of distance ladders and the cosmic microwave background. This best value relies solely on maser-based distance and velocity measurements, and it does not use any peculiar velocity corrections. Different approaches for correcting peculiar velocities do not modify $H_0$ by more than ${\pm}1{\sigma}$, with the full range of best-fit Hubble constant values spanning 71.8-76.9 km s$^{-1}$ Mpc$^{-1}$. We corroborate prior indications that the local value of $H_0$ exceeds the early-Universe value, with a confidence level varying from 95-99% for different treatments of the peculiar velocities., Comment: 13 pages, 1 figure, accepted for publication in ApJL

Published
2020
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4. The Megamaser Cosmology Project. XI. A geometric distance to CGCG 074-064

Author

Pesce, D. W., Braatz, J. A., Reid, M. J., Condon, J. J., Gao, F., Henkel, C., Kuo, C. Y., Lo, K. Y., and Zhao, W.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

As part of the survey component of the Megamaser Cosmology Project, we have discovered a disk megamaser system in the galaxy CGCG 074-064. Using the GBT and the VLA, we have obtained spectral monitoring observations of this maser system at a monthly cadence over the course of two years. We find that the systemic maser features display line-of-sight accelerations of ~4.4 km s$^{-1}$ yr$^{-1}$ that are nearly constant with velocity, while the high-velocity maser features show accelerations that are consistent with zero. We have also used the HSA to make a high-sensitivity VLBI map of the maser system in CGCG 074-064, which reveals that the masers reside in a thin, edge-on disk with a diameter of ~1.5 mas (0.6 pc). Fitting a three-dimensional warped disk model to the data, we measure a black hole mass of $2.42^{+0.22}_{-0.20} \times 10^7$ M$_{\odot}$ and a geometric distance to the system of $87.6^{+7.9}_{-7.2}$ Mpc. Assuming a CMB-frame recession velocity of $7308 \pm 150$ km s$^{-1}$, we constrain the Hubble constant to $H_0 = 81.0^{+7.4}_{-6.9}$ (stat.) $\pm 1.4$ (sys.) km s$^{-1}$ Mpc$^{-1}$., Comment: 22 pages, 6 figures, accepted for publication in ApJ

Published
2020
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5. An Improved Distance to NGC 4258 and its Implications for the Hubble Constant

Author

Reid, M. J., Pesce, D. W., and Riess, A. G.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant (Ho). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and very long baseline interferometric observations of their positions, velocities, and accelerations can be modeled to give a geometric estimate of the angular-diameter distance to the galaxy. We have improved the technique to obtain model parameter values, reducing both statistical and systematic uncertainties compared to previous analyses. We find the distance to NGC 4258 to be 7.576 +/- 0.082 (stat.) +/- 0.076 (sys.) Mpc. Using this as the sole source of calibration of the Cepheid-SN Ia distance ladder results in Ho = 72.0 +/- 1.9 km/s/Mpc, and in concert with geometric distances from Milky Way parallaxes and detached eclipsing binaries in the LMC we find Ho = 73.5 +/- 1.4 km/s/Mpc. The improved distance to NGC 4258 also provides a new calibration of the tip of the red giant branch of M_{F814W} = -4.01 +/- 0.04$ mag, with reduced systematic errors for the determination of Ho compared to the LMC-based calibration, because it is measured on the same Hubble Space Telescope photometric system and through similarly low extinction as SN Ia host halos. The result is Ho = 71.1 +/- 1.9 km/s/Mpc, in good agreement with the result from the Cepheid route, and there is no difference in Ho when using the same calibration from NGC 4258 and the same SN Ia Hubble diagram intercept to start and end both distance ladders., Comment: As will be published in ApJ (15 pages; 4 tables; 1 figure)

Published
2019
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6. The Megamaser Cosmology Project. X. High Resolution Maps and Mass Constraint for SMBHs

Author

Zhao, W., Braatz, J. A., Condon, J. J., Lo, K. Y., Reid, M. J., Henkel, C., Pesce, D. W., Greene, J. E., Gao, F., Kuo, C. Y., and Impellizzeri, C. M. V.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present high resolution (sub-mas) VLBI maps of nuclear H2O megamasers for seven galaxies. In UGC6093, the well-aligned systemic masers and high-velocity masers originate in an edge-on, flat disk and we determine the mass of the central SMBH to be M_SMBH = 2.58*10^7Msun(+-7%). For J1346+5228, the distribution of masers is consistent with a disk, but the faint high-velocity masers are only marginally detected, and we constrain the mass of the SMBH to be in the range 1.5-2.0*10^7Msun. The origin of the masers in Mrk1210 is less clear, as the systemic and high-velocity masers are misaligned and show a disorganized velocity structure. We present one possible model in which the masers originate in a tilted, warped disk, but we do not rule out the possibility of other explanations including outflow masers. In NGC6926, we detect a set of redshifted masers, clustered within a pc of each other, and a single blueshifted maser about 4.4pc away, an offset that would be unusually large for a maser disk system. Nevertheless, if it is a disk system, we estimate the enclosed mass to be M_SMBH<4.8*10^7 Msun . For NGC5793, we detect redshifted masers spaced about 1.4pc from a clustered set of blueshifted features. The orientation of the structure supports a disk scenario as suggested by Hagiwara et al.(2001). We estimate the enclosed mass to be M SMBH<1.3*10^7 Msun. For NGC2824 and J0350-0127, the masers may be associated with pc or sub-pc scale jets or outflows., Comment: Accepted by ApJ

Published
2018
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7. The Megamaser Cosmology Project.IX. Black hole masses for three maser galaxies

Author

Gao, F., Braatz, J. A., Reid, M. J., Condon, J. J., Greene, J. E., Henkel, C., Impellizzeri, C. M. V., Lo, K. Y., Kuo, C. Y., Pesce, D. W., Wagner, J., and Zhao, W.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

As part of the Megamaser Cosmology Project (MCP), we present VLBI maps of nuclear water masers toward five galaxies. The masers originate in sub-parsec circumnuclear disks. For three of the galaxies, we fit Keplerian rotation curves to estimate their supermassive black hole (SMBH) masses, and determine (2.9 $\pm$ 0.3) $\times~10^{6}M_\odot$ for J0437+2456, (1.7 $\pm$ 0.1) $\times~10^{7}M_\odot$ for ESO 558$-$G009, and (1.1 $\pm$ 0.2) $\times~10^{7}M_\odot$ for NGC 5495. In the other two galaxies, Mrk 1029 and NGC 1320, the geometry and dynamics are more complicated and preclude robust black hole mass estimates. Including our new results, we compiled a list of 15 VLBI-confirmed disk maser galaxies with robust SMBH mass measurements. With this sample, we confirm the empirical relation of $R_{out} \propto 0.3 M_{SMBH}$ reported in Wardle & Yusef-Zadeh (2012). We also find a tentative correlation between maser disk outer radii and WISE luminosity. We find no correlations of maser disk size with X-ray 2-10 keV luminosity or [O III] luminosity., Comment: Accepted for publication in ApJ

Published
2016
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8. Submillimeter H$_2$O megamasers in NGC 4945 and the Circinus galaxy

Author

Pesce, D. W., Braatz, J. A., and Impellizzeri, C. M. V.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present 321 GHz observations of five AGN from ALMA Cycle 0 archival data: NGC 5793, NGC 1068, NGC 1386, NGC 4945, and the Circinus galaxy. Submillimeter maser emission is detected for the first time towards NGC 4945, and we present a new analysis of the submillimeter maser system in Circinus. None of the other three galaxies show maser emission, though we have detected and imaged the continuum from every galaxy. Both NGC 4945 and Circinus are known to host strong ($\gtrsim 10$ Jy) 22 GHz megamaser emission, and VLBI observations have shown that the masers reside in the innermost $\sim 1$ parsec of the galaxies. The peak flux densities of the 321 GHz masers in both systems are substantially weaker (by a factor of $\sim$100) than what is observed at 22 GHz, though the corresponding isotropic luminosities are more closely matched (within a factor of $\sim$10) between the two transitions. We compare the submillimeter spectra presented here to the known 22 GHz spectra in both galaxies, and we argue that while both transitions originate from the gaseous environment near the AGN, not all sites are necessarily in common. In Circinus, the spectral structure of the 321 GHz masers indicates that they may trace the accretion disk at radii interior to the 22 GHz masers. The continuum emission in NGC 4945 and NGC 5793 shows a spatial distribution indicative of an origin in the galactic disks (likely thermal dust emission), while for the other three galaxies the emission is centrally concentrated and likely originates from the nucleus., Comment: 9 pages, 3 figures, accepted for publication in ApJ

Published
2016
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9. Origins space telescope: from first light to life

Author

Wiedner, M. C., Aalto, S., Armus, L., Bergin, E., Birkby, J., Bradford, C. M., Burgarella, D., Caselli, P., Charmandaris, V., Cooray, A., De Beck, E., Desert, J. M., Gerin, M., Goicoechea, J., Griffin, M., Hartogh, P., Helmich, F., Hogerheijde, M., Hunt, L., Karska, A., Kral, Q., Leisawitz, D., Melnick, G., Meixner, M., Matsuura, M., Milam, S., Pearson, C., Pesce, D. W., Pontoppidan, K. M., Pope, A., Rigopoulou, D., Roellig, T., Sakon, I., Staguhn, J., and Stevenson, K.

Published
2021
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10. The Megamaser Cosmology Project VIII. A Geometric Distance to NGC 5765b

Author

Gao, F., Braatz, J. A., Reid, M. J., Lo, K. Y., Condon, J. J., Henkel, C., Kuo, C. Y., Impellizzeri, C. M. V., Pesce, D. W., and Zhao, W.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

As part of the Megamaser Cosmology Project (MCP), here we present a new geometric distance measurement to the megamaser galaxy NGC 5765b. Through a series of VLBI observations, we have confirmed the water masers trace a thin, sub-parsec Keplerian disk around the nucleus, implying an enclosed mass of 4.55 $\pm$ 0.40 $\times~10^{7}M_\odot$. Meanwhile, from single dish monitoring of the maser spectra over two years, we measured the secular drifts of maser features near the systemic velocity of the galaxy with rates between 0.5 and 1.2 km s$^{-1}$ yr$^{-1}$. Fitting a warped, thin disk model to these measurements, we determine a Hubble Constant $H_{0}$ of 66.0 $\pm$ 6.0 km s$^{-1}$ Mpc$^{-1}$ with the angular-diameter distance to NGC 5765b of 126.3 $\pm$ 11.6 Mpc. Apart from the distance measurement, we also investigate some physical properties related to the maser disk in NGC 5765b. The high-velocity features are spatially distributed into several clumps, which may indicate the existence of a spiral density wave associated with the accretion disk. For the red-shifted features, the envelope defined by the peak maser intensities increases with radius. The profile of the systemic masers in NGC 5765b is smooth and shows almost no structural changes over the two years of monitoring time, which differs from the more variable case of NGC 4258., Comment: 49 pages, 11 figures, 9 tables; Accepted by ApJ

Published
2015
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11. What determines the boundaries of H2O maser emission in an X-ray illuminated gas disc?

Author

Kuo, C Y, Gao, F, Braatz, J A, Pesce, D W, Humphreys, E M L, Reid, M J, Impellizzeri, C M V, Henkel, C, Wagner, J, and Wu, C E

Subjects
COAL gas, MASERS, GAS distribution, HUBBLE constant, ACTIVE galaxies
Abstract

High precision mapping of H |$_{2}$| O megamaser emission from active galaxies has revealed more than a dozen Keplerian H |$_{2}$| O maser discs, which enable a |$\sim$| 4 per cent uncertainty estimate of the Hubble constant as well as providing accurate masses for the central black holes. These discs often have well-defined inner and outer boundaries of maser emission on sub-parsec scales. In order to better understand the physical conditions that determine the inner and outer radii of a maser disc, we examine the distributions of gas density and X-ray heating rate in a warped molecular disc described by a power-law surface density profile. For a suitable choice of the disc mass, we find that the outer radius |$R_{\rm out}$| of the maser disc predicted from our model can match the observed value, with |$R_{\rm out}$| mainly determined by the maximum heating rate or the minimum density for efficient maser action, depending on the combination of the Eddington ratio, black hole mass, and disc mass. Our analysis also indicates that the inner radius for maser action is comparable to the dust sublimation radius, suggesting that dust may play a role in determining the inner radius of a maser disc. Finally, our model predicts that H |$_{2}$| O gigamaser discs could exist at the centres of high-z quasars, with disc sizes of |$\gtrsim 10-30$| pc. [ABSTRACT FROM AUTHOR]

Published
2024
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13. The Megamaser Cosmology Project. VI. Observations of NGC 6323

Author

Kuo, C. Y., Braatz, J. A., Lo, K. Y., Reid, M. J., Suyu, S. H., Pesce, D. W., Condon, J. J., Henkel, C., and Impellizzeri, C. M. V.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present observations of the H2O megamasers in the accretion disk of NGC 6323. By combining interferometric and spectral monitoring data, we estimate H$_{0} = 73^{+26}_{-22}$ km/s/Mpc, where the low strength of the systemic masers (<15 mJy) limits the accuracy of this estimate. The methods developed here for dealing with weak maser emission provide guidance for observations of similar sources, until significant increases in radio telescope sensitivity, such as anticipated from the next generation Very Large Array, are realized., Comment: 17 pages, 7 figures, 4 tables; Accepted by ApJ; in press

Published
2014
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14. IC 485: A new candidate disc-maser galaxy at ∼100 Mpc: Milliarcsecond resolution study of the galaxy nucleus and the H2O megamaser.

Author

Ladu, E., Tarchi, A., Castangia, P., Surcis, G., Braatz, J. A., Panessa, F., and Pesce, D. W.

Subjects
ACTIVE galactic nuclei, SEYFERT galaxies, SUPERMASSIVE black holes, MASERS, ACCRETION disks
Abstract

Context. Masers are a unique tool with which to investigate the emitting gas in the innermost regions of active galactic nuclei and to map accretion discs and tori orbiting around supermassive black holes. IC 485, which is classified as a low ionisation nuclear emission-line region (LINER) or Seyfert galaxy, hosts a bright H2O maser whose nature is still unclear. Indeed, the maser could be a nuclear disc maser, a jet or outflow maser, or even the very first example of a so-called inclined water maser disc. Aims. We aim to clarify and investigate the nature of the H2O maser in IC 485 by determining the location and distribution of the maser emission at milliarcsecond resolution and by associating it with the main nuclear components of the galaxy. In a broader context, this work might also provide further information that could be used to better understand the physics and disc–jet geometry in LINER or Seyfert galaxies. Methods. We observed the nuclear region of IC 485 in continuum and spectral-line mode with the Very Long Baseline Array (VLBA) and with the European VLBI Network (EVN). Here, we report multi-epoch (six epochs) and multi-band (three bands: L, C, and K) observations made in 2018, with linear scales from ∼3 to 0.2 pc. Results. We detected two 22 GHz H2O maser components separated in velocity by 472 km s−1, with one centred at the systemic velocity of the nuclear region of IC 485 and the other at a redshifted velocity. We measured for the first time the absolute positions of these components with an accuracy of better than one milliarcsecond. Under the assumption of a maser associated with an edge-on disc in Keplerian rotation, the estimated enclosed mass is MBH = 1.2 × 107 M⊙, which is consistent with the expected mass for a SMBH in a LINER or Seyfert galaxy. Continuum compact sources have also been detected in the nuclear region of the galaxy, although at a low level of significance. Conclusions. The linear distribution of the detected maser components and a comparison with the high-sensitivity single-dish spectrum strongly suggest that the bulk of the maser emission is associated with an edge-on accretion disc. This makes IC 485 a new candidate disc-maser galaxy at a distance of 122 Mpc. In particular, thanks to the upcoming radio facilities (e.g., the Square Kilometer Array and the next-generation Very Large Array), IC 485 will play an important role – alongside other sources at similar distances – in our understanding of active galactic nuclei in an unexplored volume of the Universe. [ABSTRACT FROM AUTHOR]

Published
2024
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15. What Determines the Physical Size of a H2O Megamaser Disk ?

Author

Kuo, C. Y., Gao, F., Braatz, J. A., Pesce, D. W., Humphreys, E. M. L., Reid, M. J., Impellizzeri, C. M. V., Henkel, C., Wagner, J., Wu, C. E., Kuo, C. Y., Gao, F., Braatz, J. A., Pesce, D. W., Humphreys, E. M. L., Reid, M. J., Impellizzeri, C. M. V., Henkel, C., Wagner, J., and Wu, C. E.

Abstract

High precision mapping of H2O megamaser emissions from active galaxies have revealed more than a dozen of Keplerian H2O aser disks that enable a ~4% Hubble constant measurement and provide accurate black hole masses. The maser disks that allow for these important astrophysical applications usually display clear inner and outer edges at sub-parsec scales. It is still unclear what causes these boundaries and how their radii are determined. To understand whether the physical conditions favorable for population inversion of H2O molecules can determine the inner and outer radii of a maser disk, we examine the distributions of gas density and X-ray heating rate in a warped molecular disk described by power-law surface density profile. With a suitable choice of the disk mass, we find that the outer radius R_out of the maser disk predicted from our model can match the observed value, with R_out mainly determined by the maximum heating rate or the minimum density for efficient maser action, depending on the combination of the Eddington ratio, black hole mass and disk mass. Our analysis also suggests that the inner edge of a maser disk often lie close to the dust sublimation radius, suggesting that the physical conditions of the dusts may play a role in defining inner boundary of the disk. Finally, our model predicts that H2O "gigamaser" disks could possibly exist at the center of high-z quasars, with disk size of >~10-30 pc., Comment: To be submitted, 13 pages, 5 figures, 2 tables

Published
2023

16. Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Author

Algaba, J. C., Anczarski, J., Asada, K., Baloković, M., Chandra, S., Cui, Y. -Z, Falcone, A. D., Giroletti, M., Goddi, C., Hada, K., Haggard, D., Jorstad, S., Kaur, A., Kawashima, T., Keating, G., Kim, J. -Y, Kino, M., Komossa, S., Kravchenko, E. V., Krichbaum, T. P., Lee, S. -S, Lu, R. -S, Lucchini, M., Markoff, S., Neilsen, J., Nowak, M. A., Park, J., Principe, G., Ramakrishnan, V., Reynolds, M. T., Sasada, M., Savchenko, S. S., Williamson, K. E., Akiyama, K., Alberdi, A., Alef, W., Anantua, R., Azulay, R., Baczko, A. -K, Ball, D., Barrett, J., Bintley, D., Benson, B. A., Blackburn, L., Blundell, R., Boland, W., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y, Carlstrom, J. E., Chael, A., Chan, C. -K, Chatterjee, S., Chatterjee, K., Chen, M. -T, Chen, Y., Chesler, P. M., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., García, R., Gentaz, O., Georgiev, B., Gold, R., Gómez, J. L., Gómez-Ruiz, A. I., Gu, M., Gurwell, M., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -WL., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jiménez-Rosales, A., Johnson, M. D., Jung, T., Karami, M., Karuppusamy, R., Kettenis, M., Kim, D. -J, Kim, J., Koay, J. Y., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C. -Y, Lauer, T. R., Levis, A., Li, Y. -R, Li, Z., Lindqvist, M., Lico, R., Lindahl, G., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P, Lobanov, A. P., Loinard, L., Lonsdale, C., Macdonald, N. R., Mao, J., Marchili, N., Marrone, D. P., Marscher, A. P., Martí-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., MÃŒller, C., Musoke, G., Mejías, A. M., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-León, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L, Pesce, D. W., Piétu, V., Plambeck, R., Popstefanija, A., Porth, O., Pötzl, F. M., Prather, B., Preciado-López, J. A., Psaltis, D., Pu, H. -Y, Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sánchez, S., Sánchez-Arguelles, D., Savolainen, T., Schloerb, F. P., Schuster, K. -F, Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F, Zensus, J. A., Zhao, G. -Y, Zhao, S. -S, D’Ammando, F., Orienti, M., Abdalla, H., Adam, R., Aharonian, F., Benkhali, F. A., AngÃŒner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Barbosa Martins, V., Barnacka, A., Barnard, M., Becherini, Yvonne, Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., De Bony De Lavergne, M., Breuhaus, M., Brun, F., Brun, P., Bryan, M., BÃŒchele, M., Bulik, T., Bylund, Tomas, Caroff, S., Carosi, A., Casanova, S., Chand, T., Chen, A., Cotter, G., CuryÅ‚o, M., Damascene Mbarubucyeye, J., Davids, I. D., Davies, J., Deil, C., Devin, J., Dewilt, P., Dirson, L., Djannati-Ataï, A., Dmytriiev, A., Donath, A., Doroshenko, V., Duffy, C., Dyks, J., Egberts, K., Eichhorn, F., Einecke, S., Emery, G., Ernenwein, J. -P, Feijen, K., Fegan, S., Fiasson, A., De Clairfontaine, G. F., Fontaine, G., Funk, S., FÌßling, M., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H, Hahn, J., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Hörbe, M., Horns, D., Huber, D., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jardin-Blicq, A., Joshi, V., Jung-Richardt, I., Kasai, E., Kastendieck, M. A., KatarzyÅ„ski, K., Katz, U., Khangulyan, D., Khélifi, B., Klepser, S., Kluźniak, W., Komin, N., Konno, R., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P, Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Martí-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Moderski, R., Mohamed, M., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Nayerhoda, A., De Naurois, M., Ndiyavala, H., Niederwanger, F., Niemiec, J., Oakes, L., O’Brien, P., Odaka, H., Ohm, S., Olivera-Nieto, L., De Ona Wilhelmi, E., Ostrowski, M., Panter, M., Panny, S., Parsons, R. D., Peron, G., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Noel, A. P., Prokhorov, D. A., Prokoph, H., PÃŒhlhofer, G., Punch, Michael, Quirrenbach, A., Rauth, R., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Rieger, F., Rinchiuso, L., Romoli, C., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sailer, S., Sanchez, D. A., Santangelo, A., Sasaki, M., Scalici, M., Schutte, H. M., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, Ł., Sun, L., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Tiziani, D., Tluczykont, M., Tomankova, L., Trichard, C., Tsirou, M., Tuffs, R., Uchiyama, Y., Van Der Walt, D. J., Van Eldik, C., Van Rensburg, C., Van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Y. W., Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zorn, J., Zouari, S., Å»ywucka, N., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. A., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., De Almeida, U. B., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., BoÅ¡njak, Åœ., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D’Amico, G., D’Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., HÃŒtten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jiménez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Penil, P., Perennes, C., Persic, M., Moroni, P. G. P., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Å nidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zarić, D., Adams, C. B., Benbow, W., Brill, A., Capasso, M., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Errando, M., Farrell, K. A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Gent, A., Giuri, C., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Jin, W., Kaaret, P., Kertzman, M., Kieda, D., Kumar, S., Lang, M. J., Lundy, M., Maier, G., Moriarty, P., Mukherjee, R., Nieto, D., Nievas-Rosillo, M., O’Brien, S., Ong, R. A., Otte, A. N., Patel, S., Pfrang, K., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Richards, G. T., Roache, E., Rulten, C., Ryan, J. L., Santander, M., Sembroski, G. H., Shang, R., Weinstein, A., Williams, D. A., Williamson, T. J., Hirota, T., Cui, L., Niinuma, K., Ro, H., Sakai, N., Sawada-Satoh, S., Wajima, K., Wang, N., Liu, X., Yonekura, Y., Algaba, J. C., Anczarski, J., Asada, K., Baloković, M., Chandra, S., Cui, Y. -Z, Falcone, A. D., Giroletti, M., Goddi, C., Hada, K., Haggard, D., Jorstad, S., Kaur, A., Kawashima, T., Keating, G., Kim, J. -Y, Kino, M., Komossa, S., Kravchenko, E. V., Krichbaum, T. P., Lee, S. -S, Lu, R. -S, Lucchini, M., Markoff, S., Neilsen, J., Nowak, M. A., Park, J., Principe, G., Ramakrishnan, V., Reynolds, M. T., Sasada, M., Savchenko, S. S., Williamson, K. E., Akiyama, K., Alberdi, A., Alef, W., Anantua, R., Azulay, R., Baczko, A. -K, Ball, D., Barrett, J., Bintley, D., Benson, B. A., Blackburn, L., Blundell, R., Boland, W., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y, Carlstrom, J. E., Chael, A., Chan, C. -K, Chatterjee, S., Chatterjee, K., Chen, M. -T, Chen, Y., Chesler, P. M., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., García, R., Gentaz, O., Georgiev, B., Gold, R., Gómez, J. L., Gómez-Ruiz, A. I., Gu, M., Gurwell, M., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -WL., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jiménez-Rosales, A., Johnson, M. D., Jung, T., Karami, M., Karuppusamy, R., Kettenis, M., Kim, D. -J, Kim, J., Koay, J. Y., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C. -Y, Lauer, T. R., Levis, A., Li, Y. -R, Li, Z., Lindqvist, M., Lico, R., Lindahl, G., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P, Lobanov, A. P., Loinard, L., Lonsdale, C., Macdonald, N. R., Mao, J., Marchili, N., Marrone, D. P., Marscher, A. P., Martí-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., MÃŒller, C., Musoke, G., Mejías, A. M., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-León, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L, Pesce, D. W., Piétu, V., Plambeck, R., Popstefanija, A., Porth, O., Pötzl, F. M., Prather, B., Preciado-López, J. A., Psaltis, D., Pu, H. -Y, Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sánchez, S., Sánchez-Arguelles, D., Savolainen, T., Schloerb, F. P., Schuster, K. -F, Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F, Zensus, J. A., Zhao, G. -Y, Zhao, S. -S, D’Ammando, F., Orienti, M., Abdalla, H., Adam, R., Aharonian, F., Benkhali, F. A., AngÃŒner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Barbosa Martins, V., Barnacka, A., Barnard, M., Becherini, Yvonne, Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., De Bony De Lavergne, M., Breuhaus, M., Brun, F., Brun, P., Bryan, M., BÃŒchele, M., Bulik, T., Bylund, Tomas, Caroff, S., Carosi, A., Casanova, S., Chand, T., Chen, A., Cotter, G., CuryÅ‚o, M., Damascene Mbarubucyeye, J., Davids, I. D., Davies, J., Deil, C., Devin, J., Dewilt, P., Dirson, L., Djannati-Ataï, A., Dmytriiev, A., Donath, A., Doroshenko, V., Duffy, C., Dyks, J., Egberts, K., Eichhorn, F., Einecke, S., Emery, G., Ernenwein, J. -P, Feijen, K., Fegan, S., Fiasson, A., De Clairfontaine, G. F., Fontaine, G., Funk, S., FÌßling, M., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H, Hahn, J., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Hörbe, M., Horns, D., Huber, D., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jardin-Blicq, A., Joshi, V., Jung-Richardt, I., Kasai, E., Kastendieck, M. A., KatarzyÅ„ski, K., Katz, U., Khangulyan, D., Khélifi, B., Klepser, S., Kluźniak, W., Komin, N., Konno, R., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P, Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Martí-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Moderski, R., Mohamed, M., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Nayerhoda, A., De Naurois, M., Ndiyavala, H., Niederwanger, F., Niemiec, J., Oakes, L., O’Brien, P., Odaka, H., Ohm, S., Olivera-Nieto, L., De Ona Wilhelmi, E., Ostrowski, M., Panter, M., Panny, S., Parsons, R. D., Peron, G., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Noel, A. P., Prokhorov, D. A., Prokoph, H., PÃŒhlhofer, G., Punch, Michael, Quirrenbach, A., Rauth, R., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Rieger, F., Rinchiuso, L., Romoli, C., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sailer, S., Sanchez, D. A., Santangelo, A., Sasaki, M., Scalici, M., Schutte, H. M., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, Ł., Sun, L., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Tiziani, D., Tluczykont, M., Tomankova, L., Trichard, C., Tsirou, M., Tuffs, R., Uchiyama, Y., Van Der Walt, D. J., Van Eldik, C., Van Rensburg, C., Van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Y. W., Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zorn, J., Zouari, S., Å»ywucka, N., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. A., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., De Almeida, U. B., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., BoÅ¡njak, Åœ., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D’Amico, G., D’Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., HÃŒtten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jiménez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Penil, P., Perennes, C., Persic, M., Moroni, P. G. P., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Å nidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zarić, D., Adams, C. B., Benbow, W., Brill, A., Capasso, M., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Errando, M., Farrell, K. A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Gent, A., Giuri, C., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Jin, W., Kaaret, P., Kertzman, M., Kieda, D., Kumar, S., Lang, M. J., Lundy, M., Maier, G., Moriarty, P., Mukherjee, R., Nieto, D., Nievas-Rosillo, M., O’Brien, S., Ong, R. A., Otte, A. N., Patel, S., Pfrang, K., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Richards, G. T., Roache, E., Rulten, C., Ryan, J. L., Santander, M., Sembroski, G. H., Shang, R., Weinstein, A., Williams, D. A., Williamson, T. J., Hirota, T., Cui, L., Niinuma, K., Ro, H., Sakai, N., Sawada-Satoh, S., Wajima, K., Wang, N., Liu, X., and Yonekura, Y.

Abstract

In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∌6.5 × 109 M oË™. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded. © 2021. The Author(s). Published by the American Astronomical Society..

Published
2021
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17. SYMBA: An end-to-end VLBI synthetic data generation pipeline

Author

Roelofs, F., primary, Janssen, M., additional, Natarajan, I., additional, Deane, R., additional, Davelaar, J., additional, Olivares, H., additional, Porth, O., additional, Paine, S. N., additional, Bouman, K. L., additional, Tilanus, R. P. J., additional, van Bemmel, I. M., additional, Falcke, H., additional, Akiyama, K., additional, Alberdi, A., additional, Alef, W., additional, Asada, K., additional, Azulay, R., additional, Baczko, A., additional, Ball, D., additional, Baloković, M., additional, Barrett, J., additional, Bintley, D., additional, Blackburn, L., additional, Boland, W., additional, Bower, G. C., additional, Bremer, M., additional, Brinkerink, C. D., additional, Brissenden, R., additional, Britzen, S., additional, Broderick, A. E., additional, Broguiere, D., additional, Bronzwaer, T., additional, Byun, D., additional, Carlstrom, J. E., additional, Chael, A., additional, Chan, C., additional, Chatterjee, S., additional, Chatterjee, K., additional, Chen, M., additional, Chen, Y., additional, Cho, I., additional, Christian, P., additional, Conway, J. E., additional, Cordes, J. M., additional, Crew, G. B., additional, Cui, Y., additional, De Laurentis, M., additional, Dempsey, J., additional, Desvignes, G., additional, Dexter, J., additional, Doeleman, S. S., additional, Eatough, R. P., additional, Fish, V. L., additional, Fomalont, E., additional, Fraga-Encinas, R., additional, Friberg, P., additional, Fromm, C. M., additional, Gómez, J. L., additional, Galison, P., additional, Gammie, C. F., additional, García, R., additional, Gentaz, O., additional, Georgiev, B., additional, Goddi, C., additional, Gold, R., additional, Gu, M., additional, Gurwell, M., additional, Hada, K., additional, Hecht, M. H., additional, Hesper, R., additional, Ho, L. C., additional, Ho, P., additional, Honma, M., additional, Huang, C. L., additional, Huang, L., additional, Hughes, D. H., additional, Ikeda, S., additional, Inoue, M., additional, Issaoun, S., additional, James, D. J., additional, Jannuzi, B. T., additional, Jeter, B., additional, Jiang, W., additional, Johnson, M. D., additional, Jorstad, S., additional, Jung, T., additional, Karami, M., additional, Karuppusamy, R., additional, Kawashima, T., additional, Keating, G. K., additional, Kettenis, M., additional, Kim, J., additional, Kino, M., additional, Koay, J. Y., additional, Koch, P. M., additional, Koyama, S., additional, Kramer, M., additional, Kramer, C., additional, Krichbaum, T. P., additional, Kuo, C., additional, Lauer, T. R., additional, Lee, S., additional, Li, Y., additional, Li, Z., additional, Lindqvist, M., additional, Lico, R., additional, Liu, K., additional, Liuzzo, E., additional, Lo, W., additional, Lobanov, A. P., additional, Loinard, L., additional, Lonsdale, C., additional, Lu, R., additional, MacDonald, N. R., additional, Mao, J., additional, Markoff, S., additional, Marrone, D. P., additional, Marscher, A. P., additional, Martí-Vidal, I., additional, Matsushita, S., additional, Matthews, L. D., additional, Medeiros, L., additional, Menten, K. M., additional, Mizuno, Y., additional, Mizuno, I., additional, Moran, J. M., additional, Moriyama, K., additional, Moscibrodzka, M., additional, Müller, C., additional, Nagai, H., additional, Nagar, N. M., additional, Nakamura, M., additional, Narayan, R., additional, Narayanan, G., additional, Neri, R., additional, Ni, C., additional, Noutsos, A., additional, Okino, H., additional, Ortiz-León, G. N., additional, Oyama, T., additional, Özel, F., additional, Palumbo, D. C. M., additional, Patel, N., additional, Pen, U., additional, Pesce, D. W., additional, Piétu, V., additional, Plambeck, R., additional, PopStefanija, A., additional, Prather, B., additional, Preciado-López, J. A., additional, Psaltis, D., additional, Pu, H., additional, Ramakrishnan, V., additional, Rao, R., additional, Rawlings, M. G., additional, Raymond, A. W., additional, Rezzolla, L., additional, Ripperda, B., additional, Rogers, A., additional, Ros, E., additional, Rose, M., additional, Roshanineshat, A., additional, Rottmann, H., additional, Roy, A. L., additional, Ruszczyk, C., additional, Ryan, B. R., additional, Rygl, K. L. J., additional, Sánchez, S., additional, Sánchez-Arguelles, D., additional, Sasada, M., additional, Savolainen, T., additional, Schloerb, F. P., additional, Schuster, K., additional, Shao, L., additional, Shen, Z., additional, Small, D., additional, Won Sohn, B., additional, SooHoo, J., additional, Tazaki, F., additional, Tiede, P., additional, Titus, M., additional, Toma, K., additional, Torne, P., additional, Traianou, E., additional, Trent, T., additional, Trippe, S., additional, Tsuda, S., additional, van Langevelde, H. J., additional, van Rossum, D. R., additional, Wagner, J., additional, Wardle, J., additional, Weintroub, J., additional, Wex, N., additional, Wharton, R., additional, Wielgus, M., additional, Wong, G. N., additional, Wu, Q., additional, Young, A., additional, Young, K., additional, Younsi, Z., additional, Yuan, F., additional, Yuan, Y., additional, Zensus, J. A., additional, Zhao, G., additional, Zhao, S., additional, and Zhu, Z., additional

Published
2020
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28. First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

Author

null Event Horizon Telescope Collaboration, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Uwe Bach, Anne-Kathrin Baczko, David Ball, Mislav Baloković, John Barrett, Michi Bauböck, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Katherine L. Bouman, Geoffrey C. Bower, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamante, Do-Young Byun, John E. Carlstrom, Chiara Ceccobello, Andrew Chael, Chi-kwan Chan, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, John E. Conway, James M. Cordes, Thomas M. Crawford, Geoffrey B. Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Vedant Dhruv, Sheperd S. Doeleman, Sean Dougal, Sergio A. Dzib, Ralph P. Eatough, Razieh Emami, Heino Falcke, Joseph Farah, Vincent L. Fish, Ed Fomalont, H. Alyson Ford, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Christian M. Fromm, Antonio Fuentes, Peter Galison, Charles F. Gammie, Roberto García, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Arturo I. Gómez-Ruiz, José L. Gómez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Kari Haworth, Michael H. Hecht, Ronald Hesper, Dirk Heumann, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, C. M. Violette Impellizzeri, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jiménez-Rosales, Michael D. Johnson, Svetlana Jorstad, Abhishek V. Joshi, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Prashant Kocherlakota, Yutaro Kofuji, Patrick M. Koch, Shoko Koyama, Carsten Kramer, Michael Kramer, Thomas P. Krichbaum, Cheng-Yu Kuo, Noemi La Bella, Tod R. Lauer, Daeyoung Lee, Sang-Sung Lee, Po Kin Leung, Aviad Levis, Zhiyuan Li, Rocco Lico, Greg Lindahl, Michael Lindqvist, Mikhail Lisakov, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin J. Lonsdale, Ru-Sen Lu, Jirong Mao, Nicola Marchili, Sera Markoff, Daniel P. Marrone, Alan P. Marscher, Iván Martí-Vidal, Satoki Matsushita, Lynn D. Matthews, Lia Medeiros, Karl M. Menten, Daniel Michalik, Izumi Mizuno, Yosuke Mizuno, James M. Moran, Kotaro Moriyama, Monika Moscibrodzka, Cornelia Müller, Alejandro Mus, Gibwa Musoke, Ioannis Myserlis, Andrew Nadolski, Hiroshi Nagai, Neil M. Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Antonios Nathanail, Santiago Navarro Fuentes, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Michael A. Nowak, Junghwan Oh, Hiroki Okino, Héctor Olivares, Gisela N. Ortiz-León, Tomoaki Oyama, Feryal Özel, Daniel C. M. Palumbo, Georgios Filippos Paraschos, Jongho Park, Harriet Parsons, Nimesh Patel, Ue-Li Pen, Dominic W. Pesce, Vincent Piétu, Richard Plambeck, Aleksandar PopStefanija, Oliver Porth, Felix M. Pötzl, Ben Prather, Jorge A. Preciado-López, Dimitrios Psaltis, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Luciano Rezzolla, Angelo Ricarte, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Cristina Romero-Cañizales, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Ignacio Ruiz, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sánchez, David Sánchez-Argüelles, Miguel Sánchez-Portal, Mahito Sasada, Kaushik Satapathy, Tuomas Savolainen, F. Peter Schloerb, Jonathan Schonfeld, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, Kamal Souccar, He Sun, Fumie Tazaki, Alexandra J. Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Pablo Torne, Efthalia Traianou, Tyler Trent, Sascha Trippe, Matthew Turk, Ilse van Bemmel, Huib Jan van Langevelde, Daniel R. van Rossum, Jesse Vos, Jan Wagner, Derek Ward-Thompson, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Maciek Wielgus, Kaj Wiik, Gunther Witzel, Michael F. Wondrak, George N. Wong, Qingwen Wu, Paul Yamaguchi, Doosoo Yoon, André Young, Ken Young, Ziri Younsi, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Shuo Zhang, Guang-Yao Zhao, Shan-Shan Zhao, Claudio Agurto, Alexander Allardi, Rodrigo Amestica, Juan Pablo Araneda, Oriel Arriagada, Jennie L. Berghuis, Alessandra Bertarini, Ryan Berthold, Jay Blanchard, Ken Brown, Mauricio Cárdenas, Michael Cantzler, Patricio Caro, Edgar Castillo-Domínguez, Tin Lok Chan, Chih-Cheng Chang, Dominic O. Chang, Shu-Hao Chang, Song-Chu Chang, Chung-Chen Chen, Ryan Chilson, Tim C. Chuter, Miroslaw Ciechanowicz, Edgar Colin-Beltran, Iain M. Coulson, Joseph Crowley, Nathalie Degenaar, Sven Dornbusch, Carlos A. Durán, Wendeline B. Everett, Aaron Faber, Karl Forster, Miriam M. Fuchs, David M. Gale, Gertie Geertsema, Edouard González, Dave Graham, Frédéric Gueth, Nils W. Halverson, Chih-Chiang Han, Kuo-Chang Han, Yutaka Hasegawa, José Luis Hernández-Rebollar, Cristian Herrera, Ruben Herrero-Illana, Stefan Heyminck, Akihiko Hirota, James Hoge, Shelbi R. Hostler Schimpf, Ryan E. Howie, Yau-De Huang, Homin Jiang, Hao Jinchi, David John, Kimihiro Kimura, Thomas Klein, Derek Kubo, John Kuroda, Caleb Kwon, Richard Lacasse, Robert Laing, Erik M. Leitch, Chao-Te Li, Ching-Tang Liu, Kuan-Yu Liu, Lupin C.-C. Lin, Li-Ming Lu, Felipe Mac-Auliffe, Pierre Martin-Cocher, Callie Matulonis, John K. Maute, Hugo Messias, Zheng Meyer-Zhao, Alfredo Montaña, Francisco Montenegro-Montes, William Montgomerie, Marcos Emir Moreno Nolasco, Dirk Muders, Hiroaki Nishioka, Timothy J. Norton, George Nystrom, Hideo Ogawa, Rodrigo Olivares, Peter Oshiro, Juan Pablo Pérez-Beaupuits, Rodrigo Parra, Neil M. Phillips, Michael Poirier, Nicolas Pradel, Richard Qiu, Philippe A. Raffin, Alexandra S. Rahlin, Jorge Ramírez, Sean Ressler, Mark Reynolds, Iván Rodríguez-Montoya, Alejandro F. Saez-Madain, Jorge Santana, Paul Shaw, Leslie E. Shirkey, Kevin M. Silva, William Snow, Don Sousa, T. K. Sridharan, William Stahm, Anthony A. Stark, John Test, Karl Torstensson, Paulina Venegas, Craig Walther, Ta-Shun Wei, Chris White, Gundolf Wieching, Rudy Wijnands, Jan G. A. Wouterloot, Chen-Yu Yu, Wei Yu (于威), Milagros Zeballos, High Energy Astrophys. & Astropart. Phys (API, FNWI), Akiyama, K., Alberdi, A., Alef, W., Algaba, J. C., Anantua, R., Azulay, R., Asada, K., Bach, U., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Baubock, M., Benson, B. A., Bintley, D., Blackburn, L., Blundell, R., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Bustamante, S., Byun, D. -Y., Carlstrom, J. E., Ceccobello, C., Chael, A., Chan, C. -K., Chatterjee, K., Chatterjee, S., Chen, M. -T., Chen, Y., Cheng, X., Cho, I., Christian, P., Conroy, N. S., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Dhruv, V., Doeleman, S. S., Dougal, S., Dzib, S. A., Eatough, R. P., Emami, R., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., Gentaz, O., Georgiev, B., Garcia, R., Goddi, C., Gold, R., Gomez-Ruiz, A. I., Gomez, J. L., Gu, M., Gurwell, M., Hada, K., Haggard, D., Haworth, K., Hecht, M. H., Hesper, R., Heumann, D., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Impellizzeri, C. M. V., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jorstad, S., Joshi, A. V., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Kocherlakota, P., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, M., Krichbaum, T. P., Kuo, C. -Y., La Bella, N., Lauer, T. R., Lee, D., Lee, S. -S., Leung, P. K., Levis, A., Li, Z., Lico, R., Lindahl, G., Lindqvist, M., Lisakov, M., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C. J., Lu, R. -S., Mao, J., Marchili, N., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Michalik, D., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Mus, A., Musoke, G., Myserlis, I., Nadolski, A., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Fuentes, S. N., Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Oh, J., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Paraschos, G. F., Park, J., Parsons, H., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Potzl, F. M., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Romero-Canizales, C., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruiz, I., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sanchez-Portal, M., Sasada, M., Satapathy, K., Savolainen, T., Schloerb, F. P., Schonfeld, J., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Souccar, K., Sun, H., Tazaki, F., Tetarenko, A. J., Tilanus, R. P. J., Tiede, P., Titus, M., Torne, P., Traianou, E., Trent, T., Trippe, S., Turk, M., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Vos, J., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wiik, K., Witzel, G., Wondrak, M. F., Wong, G. N., Wu, Q., Yamaguchi, P., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhang, S., Zhao, G. -Y., Zhao, S. -S., Agurto, C., Allardi, A., Amestica, R., Araneda, J. P., Arriagada, O., Berghuis, J. L., Bertarini, A., Berthold, R., Blanchard, J., Brown, K., Cardenas, M., Cantzler, M., Caro, P., Castillo-Dominguez, E., Chan, T. L., Chang, C. -C., Chang, D. O., Chang, S. -H., Chang, S. -C., Chen, C. -C., Chilson, R., Chuter, T. C., Ciechanowicz, M., Colin-Beltran, E., Coulson, I. M., Crowley, J., Degenaar, N., Dornbusch, S., Duran, C. A., Everett, W. B., Faber, A., Forster, K., Fuchs, M. M., Gale, D. M., Geertsema, G., Gonzalez, E., Graham, D., Gueth, F., Halverson, N. W., Han, C. -C., Han, K. -C., Hasegawa, Y., Hernandez-Rebollar, J. L., Herrera, C., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Hostler Schimpf, S. R., Howie, R. E., Huang, Y. -D., Jiang, H., Jinchi, H., John, D., Kimura, K., Klein, T., Kubo, D., Kuroda, J., Kwon, C., Lacasse, R., Laing, R., Leitch, E. M., Li, C. -T., Liu, C. -T., Liu, K. -Y., Lin, L. C. -C., Lu, L. -M., Mac-Auliffe, F., Martin-Cocher, P., Matulonis, C., Maute, J. K., Messias, H., Meyer-Zhao, Z., Montana, A., Montenegro-Montes, F., Montgomerie, W., Nolasco, M. E. M., Muders, D., Nishioka, H., Norton, T. J., Nystrom, G., Ogawa, H., Olivares, R., Oshiro, P., Perez-Beaupuits, J. P., Parra, R., Phillips, N. M., Poirier, M., Pradel, N., Qiu, R., Raffin, P. A., Rahlin, A. S., Ramirez, J., Ressler, S., Reynolds, M., Rodriguez-Montoya, I., Saez-Madain, A. F., Santana, J., Shaw, P., Shirkey, L. E., Silva, K. M., Snow, W., Sousa, D., Sridharan, T. K., Stahm, W., Stark, A. A., Test, J., Torstensson, K., Venegas, P., Walther, C., Wei, T. -S., White, C., Wieching, G., Wijnands, R., Wouterloot, J. G. A., Yu, C. -Y., Yu, W., Zeballos, M., Akiyama, Kazunori [0000-0002-9475-4254], Alberdi, Antxon [0000-0002-9371-1033], Algaba, Juan Carlos [0000-0001-6993-1696], Anantua, Richard [0000-0003-3457-7660], Asada, Keiichi [0000-0001-6988-8763], Azulay, Rebecca [0000-0002-2200-5393], Bach, Uwe [0000-0002-7722-8412], Baczko, Anne-Kathrin [0000-0003-3090-3975], Baloković, Mislav [0000-0003-0476-6647], Barrett, John [0000-0002-9290-0764], Bauböck, Michi [0000-0002-5518-2812], Benson, Bradford A. [0000-0002-5108-6823], Blackburn, Lindy [0000-0002-9030-642X], Blundell, Raymond [0000-0002-5929-5857], Bouman, Katherine L. [0000-0003-0077-4367], Bower, Geoffrey C. [0000-0003-4056-9982], Boyce, Hope [0000-0002-6530-5783], Brinkerink, Christiaan D. [0000-0002-2322-0749], Brissenden, Roger [0000-0002-2556-0894], Britzen, Silke [0000-0001-9240-6734], Broderick, Avery E. [0000-0002-3351-760X], Broguiere, Dominique [0000-0001-9151-6683], Bronzwaer, Thomas [0000-0003-1151-3971], Bustamante, Sandra [0000-0001-6169-1894], Byun, Do-Young [0000-0003-1157-4109], Carlstrom, John E. [0000-0002-2044-7665], Ceccobello, Chiara [0000-0002-4767-9925], Chael, Andrew [0000-0003-2966-6220], Chan, Chi-kwan [0000-0001-6337-6126], Chatterjee, Koushik [0000-0002-2825-3590], Chatterjee, Shami [0000-0002-2878-1502], Chen, Ming-Tang [0000-0001-6573-3318], Chen, Yongjun [0000-0001-5650-6770], Cheng, Xiaopeng [0000-0003-4407-9868], Cho, Ilje [0000-0001-6083-7521], Christian, Pierre [0000-0001-6820-9941], Conroy, Nicholas S. [0000-0003-2886-2377], Conway, John E. [0000-0003-2448-9181], Cordes, James M. [0000-0002-4049-1882], Crawford, Thomas M. [0000-0001-9000-5013], Crew, Geoffrey B. [0000-0002-2079-3189], Cruz-Osorio, Alejandro [0000-0002-3945-6342], Cui, Yuzhu [0000-0001-6311-4345], Davelaar, Jordy [0000-0002-2685-2434], Laurentis, Mariafelicia De [0000-0002-9945-682X], Deane, Roger [0000-0003-1027-5043], Dempsey, Jessica [0000-0003-1269-9667], Desvignes, Gregory [0000-0003-3922-4055], Dexter, Jason [0000-0003-3903-0373], Dhruv, Vedant [0000-0001-6765-877X], Doeleman, Sheperd S. [0000-0002-9031-0904], Dougal, Sean [0000-0002-3769-1314], Dzib, Sergio A. [0000-0001-6010-6200], Eatough, Ralph P. [0000-0001-6196-4135], Emami, Razieh [0000-0002-2791-5011], Falcke, Heino [0000-0002-2526-6724], Farah, Joseph [0000-0003-4914-5625], Fish, Vincent L. [0000-0002-7128-9345], Fomalont, Ed [0000-0002-9036-2747], Ford, H. Alyson [0000-0002-9797-0972], Fraga-Encinas, Raquel [0000-0002-5222-1361], Friberg, Per [0000-0002-8010-8454], Fromm, Christian M. [0000-0002-1827-1656], Fuentes, Antonio [0000-0002-8773-4933], Galison, Peter [0000-0002-6429-3872], Gammie, Charles F. 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[0000-0002-4892-9586], Kuo, Cheng-Yu [0000-0001-6211-5581], Bella, Noemi La [0000-0002-8116-9427], Lauer, Tod R. [0000-0003-3234-7247], Lee, Daeyoung [0000-0002-3350-5588], Lee, Sang-Sung [0000-0002-6269-594X], Leung, Po Kin [0000-0002-8802-8256], Levis, Aviad [0000-0001-7307-632X], Li, Zhiyuan [0000-0003-0355-6437], Lico, Rocco [0000-0001-7361-2460], Lindahl, Greg [0000-0002-6100-4772], Lindqvist, Michael [0000-0002-3669-0715], Lisakov, Mikhail [0000-0001-6088-3819], Liu, Jun [0000-0002-7615-7499], Liu, Kuo [0000-0002-2953-7376], Liuzzo, Elisabetta [0000-0003-0995-5201], Lo, Wen-Ping [0000-0003-1869-2503], Lobanov, Andrei P. [0000-0003-1622-1484], Loinard, Laurent [0000-0002-5635-3345], Lonsdale, Colin J. [0000-0003-4062-4654], Lu, Ru-Sen [0000-0002-7692-7967], Mao, Jirong [0000-0002-7077-7195], Marchili, Nicola [0000-0002-5523-7588], Markoff, Sera [0000-0001-9564-0876], Marrone, Daniel P. [0000-0002-2367-1080], Marscher, Alan P. 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[0000-0001-6952-2147], Wu, Qingwen [0000-0003-4773-4987], Yamaguchi, Paul [0000-0002-6017-8199], Yoon, Doosoo [0000-0001-8694-8166], Young, André [0000-0003-0000-2682], Young, Ken [0000-0002-3666-4920], Younsi, Ziri [0000-0001-9283-1191], Yuan, Feng [0000-0003-3564-6437], Yuan, Ye-Fei [0000-0002-7330-4756], Zensus, J. Anton [0000-0001-7470-3321], Zhang, Shuo [0000-0002-2967-790X], Zhao, Guang-Yao [0000-0002-4417-1659], Zhao, Shan-Shan [0000-0002-9774-3606], Berghuis, Jennie L. [0000-0003-2287-158X], Blanchard, Jay [0000-0002-2756-395X], Chan, Tin Lok [0000-0001-9197-932X], Coulson, Iain M. [0000-0002-7316-4626], Degenaar, Nathalie [0000-0002-0092-3548], Durán, Carlos A. [0000-0001-7622-3890], Everett, Wendeline B. [0000-0002-5370-6651], Forster, Karl [0000-0001-5800-5531], Halverson, Nils W. [0000-0003-2606-9340], Herrero-Illana, Ruben [0000-0002-7758-8717], Hirota, Akihiko [0000-0002-0465-5421], Howie, Ryan E. [0000-0002-5451-3624], Kwon, Caleb [0000-0001-9006-7345], Laing, Robert [0000-0001-6786-3087], Leitch, Erik M. [0000-0001-8553-9336], Lin, Lupin C.-C. [0000-0003-4083-9567], Maute, John K. [0000-0002-5744-4249], Messias, Hugo [0000-0002-2985-7994], Montenegro-Montes, Francisco [0000-0002-7430-3771], Muders, Dirk [0000-0002-2315-2571], Pérez-Beaupuits, Juan Pablo [0000-0003-3536-2274], Poirier, Michael [0000-0001-6641-0959], Qiu, Richard [0000-0003-3462-0817], Rahlin, Alexandra S. [0000-0003-3953-1776], Ressler, Sean [0000-0003-0220-5723], Reynolds, Mark [0000-0003-1621-9392], Saez-Madain, Alejandro F. [0000-0002-0804-3414], Sousa, Don [0000-0002-2625-2607], Stark, Anthony A. [0000-0002-2718-9996], White, Chris [0000-0001-7448-4253], Wijnands, Rudy [0000-0002-3516-2152], Wouterloot, Jan G. A. [0000-0002-4694-6905], Yu (于威), Wei [0000-0002-5168-6052], Apollo - University of Cambridge Repository, Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, Science and Technology Facilities Council (UK), Astronomy, Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Science Support Office, Aalto-yliopisto, and Aalto University

Subjects
Black holes, F520, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, F521, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 5109 Space Sciences, Heterodyne interferometry, Galactic center, General Relativity and Quantum Cosmology, Space and Planetary Science, 5101 Astronomical Sciences, Kerr black holes, Rotating black holes, 51 Physical Sciences, Astrophysics::Galaxy Astrophysics, Mathematics
Abstract

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Full list of authors: Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Balokovic, Mislav; Barrett, John; Baubock, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom, John E.; Ceccobello, Chiara; Chael, Andrew; Chan, Chi-kwan; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dhruv, Vedant; Doeleman, Sheperd S.; Dougal, Sean; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; Garcia, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gomez-Ruiz, Arturo, I; Gomez, Jose L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C. M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Joshi, Abhishek, V; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lu, Ru-Sen; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Marti-Vidal, Ivan; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Muller, Cornelia; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Fuentes, Santiago Navarro; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares, Hector; Ortiz-Leon, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Pietu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Potzl, Felix M.; Prather, Ben; Preciado-Lopez, Jorge A.; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Romero-Canizales, Cristina; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L. J.; Sanchez, Salvador; Sanchez-Arguelles, David; Sanchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Souccar, Kamal; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Torne, Pablo; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yamaguchi, Paul; Yoon, Doosoo; Young, Andre; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan; Ozel, Feryal; Agurto, Claudio; Allardi, Alexander; Amestica, Rodrigo; Araneda, Juan Pablo; Arriagada, Oriel; Berghuis, Jennie L.; Bertarini, Alessandra; Berthold, Ryan; Blanchard, Jay; Brown, Ken; Cardenas, Mauricio; Cantzler, Michael; Caro, Patricio; Castillo-Dominguez, Edgar; Chan, Tin Lok; Chang, Chih-Cheng; Chang, Dominic O.; Chang, Shu-Hao; Chang, Song-Chu; Chen, Chung-Chen; Chilson, Ryan; Chuter, Tim C.; Ciechanowicz, Miroslaw; Colin-Beltran, Edgar; Coulson, Iain M.; Crowley, Joseph; Degenaar, Nathalie; Dornbusch, Sven; Duran, Carlos A.; Everett, Wendeline B.; Faber, Aaron; Forster, Karl; Fuchs, Miriam M.; Gale, David M.; Geertsema, Gertie; Gonzalez, Edouard; Graham, Dave; Gueth, Frederic; Halverson, Nils W.; Han, Chih-Chiang; Han, Kuo-Chang; Hasegawa, Yutaka; Hernandez-Rebollar, Jose Luis; Herrera, Cristian; Herrero-Illana, Ruben; Heyminck, Stefan; Hirota, Akihiko; Hoge, James; Schimpf, Shelbi R. Hostler; Howie, Ryan E.; Huang, Yau-De; Jiang, Homin; Jinchi, Hao; John, David; Kimura, Kimihiro; Klein, Thomas; Kubo, Derek; Kuroda, John; Kwon, Caleb; Lacasse, Richard; Laing, Robert; Leitch, Erik M.; Li, Chao-Te; Liu, Ching-Tang; Liu, Kuan-Yu; Lin, Lupin C-C; Lu, Li-Ming; Mac-Auliffe, Felipe; Martin-Cocher, Pierre; Matulonis, Callie; Maute, John K.; Messias, Hugo; Meyer-Zhao, Zheng; Montana, Alfredo; Montenegro-Montes, Francisco; Montgomerie, William; Nolasco, Marcos Emir Moreno; Muders, Dirk; Nishioka, Hiroaki; Norton, Timothy J.; Nystrom, George; Ogawa, Hideo; Olivares, Rodrigo; Oshiro, Peter; Perez-Beaupuits, Juan Pablo; Parra, Rodrigo; Phillips, Neil M.; Poirier, Michael; Pradel, Nicolas; Qiu, Richard; Raffin, Philippe A.; Rahlin, Alexandra S.; Ramirez, Jorge; Ressler, Sean; Reynolds, Mark; Rodriguez-Montoya, Ivan; Saez-Madain, Alejandro F.; Santana, Jorge; Shaw, Paul; Shirkey, Leslie E., Jr.; Silva, Kevin M.; Snow, William; Sousa, Don; Sridharan, T. K.; Stahm, William; Stark, Anthony A.; Test, John; Torstensson, Karl; Venegas, Paulina; Walther, Craig; Wei, Ta-Shun; White, Chris; Wieching, Gundolf; Wijnands, Rudy; Wouterloot, Jan G. A.; Yu, Chen-Yu; Yu, Wei; Zeballos, Milagros; Event Horizon Telescope Collaboration., We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 ± 2.3 μas (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass ∼4 × 106 M⊙, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50°), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 103–105 gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass. © 2022. The Author(s). Published by the American Astronomical Society., The Event Horizon Telescope Collaboration thanks the following organizations and programs: the Academia Sinica; the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigación y Desarrollo (ANID), Chile via NCN19_058 (TITANs) and Fondecyt 1221421, the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA and the astronomy institutes of the University of Amsterdam, Leiden University and Radboud University; the ALMA North America Development Fund; the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation (although the opinions expressed in this work are those of the author(s) and do not necessarily reflect the views of these Foundations); Chandra DD7-18089X and TM6-17006X; the China Scholarship Council; China Postdoctoral Science Foundation fellowship (2020M671266); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356); the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM, projects IN112417 and IN112820); the Dutch Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and grant OCENW.KLEIN.113; the Dutch National Supercomputers, Cartesius and Snellius (NWO Grant 2021.013); the EACOA Fellowship awarded by the East Asia Core Observatories Association, which consists of the Academia Sinica Institute of Astronomy and Astrophysics, the National Astronomical Observatory of Japan, Center for Astronomical Mega-Science, Chinese Academy of Sciences, and the Korea Astronomy and Space Science Institute; the European Research Council (ERC) Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the European Union Horizon 2020 research and innovation programme under grant agreements RadioNet (No 730562) and M2FINDERS (No 101018682); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the European Research Council for advanced grant "JETSET: Launching, propagation and emission of relativistic jets from binary mergers and across mass scales" (Grant No. 884631); the Institute for Advanced Study; the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; DFG research grant "Jet physics on horizon scales and beyond" (Grant No. FR 4069/2-1); Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships, research at the Flatiron Institute is supported by the Simons Foundation; the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT; grant JPMXP1020200109); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Joint Institute for Computational Fundamental Science, Japan; the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJSSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP21H01137, JP18H03721, JP18K13594, 18K03709, JP19K14761, 18H01245, 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (103-2119-M-001-010-MY2, 105-2112-M-001-025-MY3, 105-2119-M-001-042, 106-2112-M-001-011, 106-2119-M-001-013, 106-2119-M-001-027, 106-2923-M-001-005, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-001-041, 107-2119-M-110-005, 107-2923-M-001-009, 108-2112-M-001-048, 108-2112-M-001-051, 108-2923-M-001-002, 109-2112-M-001-025, 109-2124-M-001-005, 109-2923-M-001-001, 110-2112-M-003-007-MY2, 110-2112-M-001-033, 110-2124-M-001-007, and 110-2923-M-001-001); the Ministry of Education (MoE) of Taiwan Yushan Young Scholar Program; the Physics Division, National Center for Theoretical Sciences of Taiwan; the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, NASA NuSTAR award 80NSSC20K0645); NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555; the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2017YFA0402703, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1440254, AST-1555365, AST-1614868, AST-1615796, AST-1715061, AST-1716327, AST-1716536, OISE-1743747, AST-1816420, AST-1935980, AST-2034306); NSF Astronomy and Astrophysics Postdoctoral Fellowship (AST-1903847); the Natural Science Foundation of China (grants 11650110427, 10625314, 11721303, 11725312, 11873028, 11933007, 11991052, 11991053, 12192220, 12192223); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, the Korea Research Fellowship Program: NRF-2015H1D3A1066561, Brain Pool Program: 2019H1D3A1A01102564, Basic Research Support Grant 2019R1F1A1059721, 2021R1A6A3A01086420, 2022R1C1C1005255); Netherlands Research School for Astronomy (NOVA) Virtual Institute of Accretion (VIA) postdoctoral fellowships; Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Spanish Ministerio de Ciencia e Innovación (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21); the University of Pretoria for financial aid in the provision of the new Cluster Server nodes and SuperMicro (USA) for a SEEDING GRANT approved towards these nodes in 2020; the Shanghai Pilot Program for Basic Research, Chinese Academy of Science, Shanghai Branch (JCYJ-SHFY-2021-013); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017- 0709); the Spinoza Prize SPI 78-409; the South African Research Chairs Initiative, through the South African Radio Astronomy Observatory (SARAO, grant ID 77948), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Innovation (DSI) of South Africa; the Toray Science Foundation; Swedish Research Council (VR); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001); and the YCAA Prize Postdoctoral Fellowship. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key Research and Development Program (No. 2017YFA0402700) of China and Natural Science Foundation of China grant 11873028. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geográfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. Support for SPT participation in the EHT is provided by the National Science Foundation through award OPP-1852617 to the University of Chicago. Partial support is also provided by the Kavli Institute of Cosmological Physics at the University of Chicago. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. This research is part of the Frontera computing project at the Texas Advanced Computing Center through the Frontera Large-Scale Community Partnerships allocation AST20023. Frontera is made possible by National Science Foundation award OAC-1818253. This research was carried out using resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy Office of Science. Additional work used ABACUS2.0, which is part of the eScience center at Southern Denmark University. Simulations were also performed on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, on the HazelHen cluster at the HLRS in Stuttgart, and on the Pi2.0 and Siyuan Mark-I at Shanghai Jiao Tong University. The computer resources of the Finnish IT Center for Science (CSC) and the Finnish Computing Competence Infrastructure (FCCI) project are acknowledged. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www.calculquebec.ca) and Compute Canada (http://www.computecanada.ca).

Published
2022

29. First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass

Author

null Event Horizon Telescope Collaboration, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Uwe Bach, Anne-Kathrin Baczko, David Ball, Mislav Baloković, John Barrett, Michi Bauböck, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Katherine L. Bouman, Geoffrey C. Bower, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamante, Do-Young Byun, John E. Carlstrom, Chiara Ceccobello, Andrew Chael, Chi-kwan Chan, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, John E. Conway, James M. Cordes, Thomas M. Crawford, Geoffrey B. Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Vedant Dhruv, Sheperd S. Doeleman, Sean Dougal, Sergio A. Dzib, Ralph P. Eatough, Razieh Emami, Heino Falcke, Joseph Farah, Vincent L. Fish, Ed Fomalont, H. Alyson Ford, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Christian M. Fromm, Antonio Fuentes, Peter Galison, Charles F. Gammie, Roberto García, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Arturo I. Gómez-Ruiz, José L. Gómez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Kari Haworth, Michael H. Hecht, Ronald Hesper, Dirk Heumann, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, C. M. Violette Impellizzeri, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jiménez-Rosales, Michael D. Johnson, Svetlana Jorstad, Abhishek V. Joshi, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Prashant Kocherlakota, Yutaro Kofuji, Patrick M. Koch, Shoko Koyama, Carsten Kramer, Michael Kramer, Thomas P. Krichbaum, Cheng-Yu Kuo, Noemi La Bella, Tod R. Lauer, Daeyoung Lee, Sang-Sung Lee, Po Kin Leung, Aviad Levis, Zhiyuan Li, Rocco Lico, Greg Lindahl, Michael Lindqvist, Mikhail Lisakov, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin J. Lonsdale, Ru-Sen Lu, Jirong Mao, Nicola Marchili, Sera Markoff, Daniel P. Marrone, Alan P. Marscher, Iván Martí-Vidal, Satoki Matsushita, Lynn D. Matthews, Lia Medeiros, Karl M. Menten, Daniel Michalik, Izumi Mizuno, Yosuke Mizuno, James M. Moran, Kotaro Moriyama, Monika Moscibrodzka, Cornelia Müller, Alejandro Mus, Gibwa Musoke, Ioannis Myserlis, Andrew Nadolski, Hiroshi Nagai, Neil M. Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Antonios Nathanail, Santiago Navarro Fuentes, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Michael A. Nowak, Junghwan Oh, Hiroki Okino, Héctor Olivares, Gisela N. Ortiz-León, Tomoaki Oyama, Daniel C. M. Palumbo, Georgios Filippos Paraschos, Jongho Park, Harriet Parsons, Nimesh Patel, Ue-Li Pen, Dominic W. Pesce, Vincent Piétu, Richard Plambeck, Aleksandar PopStefanija, Oliver Porth, Felix M. Pötzl, Ben Prather, Jorge A. Preciado-López, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Luciano Rezzolla, Angelo Ricarte, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Cristina Romero-Cañizales, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Ignacio Ruiz, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sánchez, David Sánchez-Argüelles, Miguel Sánchez-Portal, Mahito Sasada, Kaushik Satapathy, Tuomas Savolainen, F. Peter Schloerb, Jonathan Schonfeld, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, Kamal Souccar, He Sun, Fumie Tazaki, Alexandra J. Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Pablo Torne, Efthalia Traianou, Tyler Trent, Sascha Trippe, Matthew Turk, Ilse van Bemmel, Huib Jan van Langevelde, Daniel R. van Rossum, Jesse Vos, Jan Wagner, Derek Ward-Thompson, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Maciek Wielgus, Kaj Wiik, Gunther Witzel, Michael F. Wondrak, George N. Wong, Qingwen Wu, Paul Yamaguchi, Doosoo Yoon, André Young, Ken Young, Ziri Younsi, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Shuo Zhang, Guang-Yao Zhao, Shan-Shan Zhao, Dominic O. Chang, Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, Swedish Research Council, Science and Technology Facilities Council (UK), High Energy Astrophys. & Astropart. Phys (API, FNWI), Astronomy, Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Science Support Office, Aalto-yliopisto, Aalto University, Akiyama, K., Alberdi, A., Alef, W., Algaba, J. C., Anantua, R., Asada, K., Azulay, R., Bach, U., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Baubock, M., Benson, B. A., Bintley, D., Blackburn, L., Blundell, R., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Bustamante, S., Byun, D. -Y., Carlstrom, J. E., Ceccobello, C., Chael, A., Chan, C. -K., Chatterjee, K., Chatterjee, S., Chen, M. -T., Chen, Y., Cheng, X., Cho, I., Christian, P., Conroy, N. S., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Dhruv, V., Doeleman, S. S., Dougal, S., Dzib, S. A., Eatough, R. P., Emami, R., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gomez-Ruiz, A. I., Gomez, J. L., Gu, M., Gurwell, M., Hada, K., Haggard, D., Haworth, K., Hecht, M. H., Hesper, R., Heumann, D., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Impellizzeri, C. M. V., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jorstad, S., Joshi, A. V., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Kocherlakota, P., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, M., Krichbaum, T. P., Kuo, C. -Y., Bella, N. L., Lauer, T. R., Lee, D., Lee, S. -S., Leung, P. K., Levis, A., Li, Z., Lico, R., Lindahl, G., Lindqvist, M., Lisakov, M., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C. J., Lu, R. -S., Mao, J., Marchili, N., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Michalik, D., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Mus, A., Musoke, G., Myserlis, I., Nadolski, A., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Fuentes, S. N., Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Oh, J., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Palumbo, D. C. M., Paraschos, G. F., Park, J., Parsons, H., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Potzl, F. M., Prather, B., Preciado-Lopez, J. A., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Romero-Canizales, C., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruiz, I., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sanchez-Portal, M., Sasada, M., Satapathy, K., Savolainen, T., Schloerb, F. P., Schonfeld, J., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Souccar, K., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Torne, P., Traianou, E., Trent, T., Trippe, S., Turk, M., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Vos, J., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wiik, K., Witzel, G., Wondrak, M. F., Wong, G. N., Wu, Q., Yamaguchi, P., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhang, S., Zhao, G. -Y., Zhao, S. -S., and Chang, D. O.

Subjects
F520, Space and Planetary Science, Black holes, Astronomy, F521, Astronomy and Astrophysics, Mathematics, Astrophysics::Galaxy Astrophysics
Abstract

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Full list of authors: Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Balokovic, Mislav; Barrett, John; Baubock, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom, John E.; Ceccobello, Chiara; Chael, Andrew; Chan, Chi-kwan; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dhruv, Vedant; Doeleman, Sheperd S.; Dougal, Sean; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; Garcia, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gomez-Ruiz, Arturo, I; Gomez, Jose L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C. M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Joshi, Abhishek, V; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lu, Ru-Sen; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Marti-Vidal, Ivan; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Muller, Cornelia; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Fuentes, Santiago Navarro; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares, Hector; Ortiz-Leon, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Pietu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Potzl, Felix M.; Prather, Ben; Preciado-Lopez, Jorge A.; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Romero-Canizales, Cristina; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L. J.; Sanchez, Salvador; Sanchez-Arguelles, David; Sanchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Souccar, Kamal; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Torne, Pablo; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yamaguchi, Paul; Yoon, Doosoo; Young, Andre; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan; Chang, Dominic O.; Event Horizon Telescope Collaboration., In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A*, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. We find that the Sgr A* data exhibit variability that exceeds what can be explained by the uncertainties in the data or by the effects of interstellar scattering. The magnitude of this variability can be a substantial fraction of the correlated flux density, reaching ∼100% on some baselines. Through an exploration of simple geometric source models, we demonstrate that ring-like morphologies provide better fits to the Sgr A* data than do other morphologies with comparable complexity. We develop two strategies for fitting static geometric ring models to the time-variable Sgr A* data; one strategy fits models to short segments of data over which the source is static and averages these independent fits, while the other fits models to the full data set using a parametric model for the structural variability power spectrum around the average source structure. Both geometric modeling and image-domain feature extraction techniques determine the ring diameter to be 51.8 ± 2.3 μas (68% credible intervals), with the ring thickness constrained to have an FWHM between ∼30% and 50% of the ring diameter. To bring the diameter measurements to a common physical scale, we calibrate them using synthetic data generated from GRMHD simulations. This calibration constrains the angular size of the gravitational radius to be ${4.8}_{-0.7}^{+1.4}$ μas, which we combine with an independent distance measurement from maser parallaxes to determine the mass of Sgr A* to be ${4.0}_{-0.6}^{+1.1}\times {10}^{6}$ M⊙. © 2022. The Author(s). Published by the American Astronomical Society., The Event Horizon Telescope Collaboration thanks the following organizations and programs: the Academia Sinica; the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigación y Desarrollo (ANID), Chile via NCN19_058 (TITANs) and Fondecyt 1221421, the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA and the astronomy institutes of the University of Amsterdam, Leiden University and Radboud University; the ALMA North America Development Fund; the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation (although the opinions expressed in this work are those of the author(s) and do not necessarily reflect the views of these Foundations); Chandra DD7-18089X and TM6-17006X; the China Scholarship Council; China Postdoctoral Science Foundation fellowship (2020M671266); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356); the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM, projects IN112417 and IN112820); the Dutch Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and grant OCENW.KLEIN.113; the Dutch National Supercomputers, Cartesius and Snellius (NWO Grant 2021.013); the EACOA Fellowship awarded by the East Asia Core Observatories Association, which consists of the Academia Sinica Institute of Astronomy and Astrophysics, the National Astronomical Observatory of Japan, Center for Astronomical Mega-Science, Chinese Academy of Sciences, and the Korea Astronomy and Space Science Institute; the European Research Council (ERC) Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the European Union Horizon 2020 research and innovation programme under grant agreements RadioNet (No 730562) and M2FINDERS (No 101018682); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the European Research Council for advanced grant 'JETSET: Launching, propagation and emission of relativistic jets from binary mergers and across mass scales' (Grant No. 884631); the Institute for Advanced Study; the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; DFG research grant "Jet physics on horizon scales and beyond" (Grant No. FR 4069/2-1); Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships, research at the Flatiron Institute is supported by the Simons Foundation; the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT; grant JPMXP1020200109); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Joint Institute for Computational Fundamental Science, Japan; the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJSSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP21H01137, JP18H03721, JP18K13594, 18K03709, JP19K14761, 18H01245, 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (103-2119-M-001-010-MY2, 105-2112-M-001-025-MY3, 105-2119-M-001-042, 106-2112-M-001-011, 106-2119-M-001-013, 106-2119-M-001-027, 106-2923-M-001-005, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-001-041, 107-2119-M-110-005, 107-2923-M-001-009, 108-2112-M-001-048, 108-2112-M-001-051, 108-2923-M-001-002, 109-2112-M-001-025, 109-2124-M-001-005, 109-2923-M-001-001, 110-2112-M-003-007-MY2, 110-2112-M-001-033, 110-2124-M-001-007, and 110-2923-M-001-001); the Ministry of Education (MoE) of Taiwan Yushan Young Scholar Program; the Physics Division, National Center for Theoretical Sciences of Taiwan; the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, NASA NuSTAR award 80NSSC20K0645); NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555; the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2017YFA0402703, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1440254, AST-1555365, AST-1614868, AST-1615796, AST-1715061, AST-1716327, AST-1716536, OISE-1743747, AST-1816420, AST-1935980, AST-2034306); NSF Astronomy and Astrophysics Postdoctoral Fellowship (AST-1903847); the Natural Science Foundation of China (grants 11650110427, 10625314, 11721303, 11725312, 11873028, 11933007, 11991052, 11991053, 12192220, 12192223); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, the Korea Research Fellowship Program: NRF-2015H1D3A1066561, Brain Pool Program: 2019H1D3A1A01102564, Basic Research Support Grant 2019R1F1A1059721, 2021R1A6A3A01086420, 2022R1C1C1005255); Netherlands Research School for Astronomy (NOVA) Virtual Institute of Accretion (VIA) postdoctoral fellowships; Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Spanish Ministerio de Ciencia e Innovación (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21); the University of Pretoria for financial aid in the provision of the new Cluster Server nodes and SuperMicro (USA) for a SEEDING GRANT approved towards these nodes in 2020; the Shanghai Pilot Program for Basic Research, Chinese Academy of Science, Shanghai Branch (JCYJ-SHFY-2021-013); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017- 0709); the Spinoza Prize SPI 78-409; the South African Research Chairs Initiative, through the South African Radio Astronomy Observatory (SARAO, grant ID 77948), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Innovation (DSI) of South Africa; the Toray Science Foundation; Swedish Research Council (VR); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001); and the YCAA Prize Postdoctoral Fellowship. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key Research and Development Program (No. 2017YFA0402700) of China and Natural Science Foundation of China grant 11873028. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geográfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. Support for SPT participation in the EHT is provided by the National Science Foundation through award OPP-1852617 to the University of Chicago. Partial support is also provided by the Kavli Institute of Cosmological Physics at the University of Chicago. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. This research is part of the Frontera computing project at the Texas Advanced Computing Center through the Frontera Large-Scale Community Partnerships allocation AST20023. Frontera is made possible by National Science Foundation award OAC-1818253. This research was carried out using resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy Office of Science. Additional work used ABACUS2.0, which is part of the eScience center at Southern Denmark University. Simulations were also performed on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, on the HazelHen cluster at the HLRS in Stuttgart, and on the Pi2.0 and Siyuan Mark-I at Shanghai Jiao Tong University. The computer resources of the Finnish IT Center for Science (CSC) and the Finnish Computing Competence Infrastructure (FCCI) project are acknowledged. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www.calculquebec.ca) and Compute Canada (http://www.computecanada.ca).

Published
2022

30. The Variability of the Black Hole Image in M87 at the Dynamical Timescale

Author

Kaushik Satapathy, Dimitrios Psaltis, Feryal Özel, Lia Medeiros, Sean T. Dougall, Chi-Kwan Chan, Maciek Wielgus, Ben S. Prather, George N. Wong, Charles F. Gammie, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Anne-Kathrin Baczko, David Ball, Mislav Baloković, John Barrett, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Wilfred Boland, Katherine L. Bouman, Geoffrey C. Bower, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamente, Do-Young Byun, John E. Carlstrom, Andrew Chael, Koushik Chatterjee, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Ilje Cho, Pierre Christian, John E. Conway, James M. Cordes, Thomas M. Crawford, Geoffrey B. Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Sheperd S. Doeleman, Ralph P. Eatough, Heino Falcke, Joseph Farah, Vincent L. Fish, Ed Fomalont, H. Alyson Ford, Raquel Fraga-Encinas, Per Friberg, Christian M. Fromm, Antonio Fuentes, Peter Galison, Roberto García, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Arturo I. Gómez-Ruiz, José L. Gómez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Michael H. Hecht, Ronald Hesper, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jimenez-Rosales, Michael D. Johnson, Svetlana Jorstad, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Yutaro Kofuji, Patrick M. Koch, Shoko Koyama, Carsten Kramer, Michael Kramer, Thomas P. Krichbaum, Cheng-Yu Kuo, Tod R. Lauer, Sang-Sung Lee, Aviad Levis, Yan-Rong Li, Zhiyuan Li, Michael Lindqvist, Rocco Lico, Greg Lindahl, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin Lonsdale, Ru-Sen Lu, Nicholas R. MacDonald, Jirong Mao, Nicola Marchili, Sera Markoff, Daniel P. Marrone, Alan P. Marscher, Iván Martí-Vidal, Satoki Matsushita, Lynn D. Matthews, Karl M. Menten, Izumi Mizuno, Yosuke Mizuno, James M. Moran, Kotaro Moriyama, Monika Moscibrodzka, Cornelia Müller, Alejandro Mus Mejías, Gibwa Musoke, Hiroshi Nagai, Neil M. Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Antonios Nathanail, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Michael A. Nowak, Hiroki Okino, Héctor Olivares, Gisela N. Ortiz-León, Tomoaki Oyama, Daniel C. M. Palumbo, Jongho Park, Nimesh Patel, Ue-Li Pen, Dominic W. Pesce, Vincent Piétu, Richard Plambeck, Aleksandar PopStefanija, Oliver Porth, Felix M. Pötzl, Jorge A. Preciado-López, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Luciano Rezzolla, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Mel Rose, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sánchez, David Sánchez-Arguelles, Mahito Sasada, Tuomas Savolainen, F. Peter Schloerb, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, He Sun, Fumie Tazaki, Alexandra J. Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Kenji Toma, Pablo Torne, Efthalia Traianou, Tyler Trent, Sascha Trippe, Ilse van Bemmel, Huib Jan van Langevelde, Daniel R. van Rossum, Jan Wagner, Derek Ward-Thompson, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Kaj Wiik, Qingwen Wu, Doosoo Yoon, André Young, Ken Young, Ziri Younsi, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Guang-Yao Zhao, Shan-Shan Zhao, Ministerio de Ciencia e Innovación (España), European Commission, National Science Foundation (US), Academy of Finland, Agencia Nacional de Investigación y Desarrollo (Chile), National Natural Science Foundation of China, National Key Research and Development Program (China), National Aeronautics and Space Administration (US), Ministry of Science and Technology (Taiwan), High Energy Astrophys. & Astropart. Phys (API, FNWI), Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Astronomy, Satapathy, K., Psaltis, D., Ozel, F., Medeiros, L., Dougall, S. T., Chan, C. -K., Wielgus, M., Prather, B. S., Wong, G. N., Gammie, C. F., Akiyama, K., Alberdi, A., Alef, W., Algaba, J. C., Anantua, R., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Benson, B. A., Bintley, D., Blackburn, L., Blundell, R., Boland, W., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Bustamente, S., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chatterjee, K., Chatterjee, S., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gomez-Ruiz, A. I., Gomez, J. L., Gu, M., Gurwell, M., Hada, K., Haggard, D., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, M., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Levis, A., Li, Y. -R., Li, Z., Lindqvist, M., Lico, R., Lindahl, G., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Marchili, N., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Menten, K. M., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Mejias, A. M., Musoke, G., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Palumbo, D. C. M., Park, J., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Potzl, F. M., Preciado-Lopez, J. A., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Traianou, E., Trent, T., Trippe, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wiik, K., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G. -Y., and Zhao, S. -S.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astronomy, SCHEME, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, F500, MASS, Black hole physics, NOISE, ENERGY, Space and Planetary Science, ACCRETION, Astrophysics - High Energy Astrophysical Phenomena, High energy astrophysics, GRMHD SIMULATIONS
Abstract

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.--Full list of authors: Satapathy, Kaushik; Psaltis, Dimitrios; Özel, Feryal; Medeiros, Lia; Dougall, Sean T.; Chan, Chi-Kwan; Wielgus, Maciek; Prather, Ben S.; Wong, George N.; Gammie, Charles F.; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamente, Sandra; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Lindahl, Greg; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Mejías, Alejandro Mus; Musoke, Gibwa; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Preciado-López, Jorge A.; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wiik, Kaj; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan., The black hole images obtained with the Event Horizon Telescope (EHT) are expected to be variable at the dynamical timescale near their horizons. For the black hole at the center of the M87 galaxy, this timescale (5–61 days) is comparable to the 6 day extent of the 2017 EHT observations. Closure phases along baseline triangles are robust interferometric observables that are sensitive to the expected structural changes of the images but are free of station-based atmospheric and instrumental errors. We explored the day-to-day variability in closure-phase measurements on all six linearly independent nontrivial baseline triangles that can be formed from the 2017 observations. We showed that three triangles exhibit very low day-to-day variability, with a dispersion of ∼3°–5°. The only triangles that exhibit substantially higher variability (∼90°–180°) are the ones with baselines that cross the visibility amplitude minima on the u–v plane, as expected from theoretical modeling. We used two sets of general relativistic magnetohydrodynamic simulations to explore the dependence of the predicted variability on various black hole and accretion-flow parameters. We found that changing the magnetic field configuration, electron temperature model, or black hole spin has a marginal effect on the model consistency with the observed level of variability. On the other hand, the most discriminating image characteristic of models is the fractional width of the bright ring of emission. Models that best reproduce the observed small level of variability are characterized by thin ring-like images with structures dominated by gravitational lensing effects and thus least affected by turbulence in the accreting plasmas. © 2022. The Author(s). Published by the American Astronomical Society., This work was supported, in part, by the NSF PIRE award 1743747 and NASA ATP award 80NSSC20K0521. L.M. acknowledges support from an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award No. AST-1903847. M.W. acknowledges the support of the Black Hole Initiative at Harvard University, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation to Harvard University. All ray tracing calculations for Set A were performed with the El Gato GPU cluster at the University of Arizona that is funded by NSF award 1228509. All analyses for Set B were performed on CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. The EHT Collaboration thanks the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496, and 315721); the Agencia Nacional de Investigación y Desarrollo, Chile via NCN19058 (TITANs) and Fondecyt 3190878; the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA, and the astronomy institutes of the University of Amsterdam, Leiden University, and Radboud University; the black hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Consejo Nacional de Ciencia y Tecnología (Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, and 263356); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (projects IN112417 and IN112820); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the Gordon and Betty Moore Foundation (grant GBMF-3561); the Istituto Nazionale di Fisica Nucleare sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships; research at the Flatiron Institute is supported by the Simons Foundation; the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS; grants QYZDJ-SSW-SLH057, QYZDJSSW-SYS008, and ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max-Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, and 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS). FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119- M-001-027, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-110-005, 108-2112-M-001-048, and 109-2124-M-001-005); the National Aeronautics and Space Administration (NASA; Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, and NASA NuSTAR award 80NSSC20K0645); the National Institute of Natural Sciences of Japan; the National Key Research and Development Program of China (grants 2016YFA0400704 and 2016YFA0400702); the National Science Foundation (NSF; grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1555365, AST-1615796, AST-1715061, AST-1716327, AST-1903847, and AST-2034306); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007, 11991052, and 11991053); a fellowship of China Postdoctoral Science Foundation (2020M671266); the Natural Sciences and Engineering Research Council of Canada (NSERC; including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752 and 2015- R1D1A1A01056807; the Korea Research Fellowship Program: NRF-2015H1D3A1066561 and Basic Research Support Grant 2019R1F1A1059721); the Netherlands Organization for Scientific Research VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Technology of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017–00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science, and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation, and Science); the Spanish Ministerio de Economía y Competitividad (grants PGC2018-098915-B-C21, AYA2016-80889-P, and PID2019-108995GB-C21); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017–0709); the Toray Science Foundation; the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC), for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001); the European Union's Horizon 2020 research and innovation program under grant agreement No. 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra DD7-18089X and TM6-17006X; the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled, in part, by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www.calculquebec.ca), and Compute Canada (http://www.computecanada.ca). We thank the staff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and the National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), MOST (Taiwan), the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and the Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the OSO (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, CAS, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30 m telescope in Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck Gesellschaft, Germany), and IGN (Instituto Geográfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the NSF through grant PLR-1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation, and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under an open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research. The EHT project is grateful to T4Science and Microsemi for their assistance with hydrogen masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018.

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2022
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31. A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

Author

Boris Georgiev, Dominic W. Pesce, Avery E. Broderick, George N. Wong, Vedant Dhruv, Maciek Wielgus, Charles F. Gammie, Chi-kwan Chan, Koushik Chatterjee, Razieh Emami, Yosuke Mizuno, Roman Gold, Christian M. Fromm, Angelo Ricarte, Doosoo Yoon, Abhishek V. Joshi, Ben Prather, Alejandro Cruz-Osorio, Michael D. Johnson, Oliver Porth, Héctor Olivares, Ziri Younsi, Luciano Rezzolla, Jesse Vos, Richard Qiu, Antonios Nathanail, Ramesh Narayan, Andrew Chael, Richard Anantua, Monika Moscibrodzka, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Keiichi Asada, Rebecca Azulay, Uwe Bach, Anne-Kathrin Baczko, David Ball, Mislav Baloković, John Barrett, Michi Bauböck, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Katherine L. Bouman, Geoffrey C. Bower, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Dominique Broguiere, Thomas Bronzwaer, Sandra Bustamante, Do-Young Byun, John E. Carlstrom, Chiara Ceccobello, Shami Chatterjee, Ming-Tang Chen, Yongjun Chen, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, John E. Conway, James M. Cordes, Thomas M. Crawford, Geoffrey B. Crew, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Jason Dexter, Sheperd S. Doeleman, Sean Dougal, Sergio A. Dzib, Ralph P. Eatough, Heino Falcke, Joseph Farah, Vincent L. Fish, Ed Fomalont, H. Alyson Ford, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Antonio Fuentes, Peter Galison, Roberto García, Olivier Gentaz, Ciriaco Goddi, Arturo I. Gómez-Ruiz, José L. Gómez, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Kari Haworth, Michael H. Hecht, Ronald Hesper, Dirk Heumann, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, C. M. Violette Impellizzeri, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jiménez-Rosales, Svetlana Jorstad, Taehyun Jung, Mansour Karami, Ramesh Karuppusamy, Tomohisa Kawashima, Garrett K. Keating, Mark Kettenis, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kim, Motoki Kino, Jun Yi Koay, Prashant Kocherlakota, Yutaro Kofuji, Patrick M. Koch, Shoko Koyama, Carsten Kramer, Michael Kramer, Thomas P. Krichbaum, Cheng-Yu Kuo, Noemi La Bella, Tod R. Lauer, Daeyoung Lee, Sang-Sung Lee, Luis Lehner, Po Kin Leung, Aviad Levis, Zhiyuan Li, Rocco Lico, Greg Lindahl, Michael Lindqvist, Mikhail Lisakov, Jun Liu, Kuo Liu, Elisabetta Liuzzo, Wen-Ping Lo, Andrei P. Lobanov, Laurent Loinard, Colin J. Lonsdale, Ru-Sen Lu, Jirong Mao, Nicola Marchili, Sera Markoff, Daniel P. Marrone, Alan P. Marscher, Iván Martí-Vidal, Satoki Matsushita, Lynn D. Matthews, Karl M. Menten, Daniel Michalik, Izumi Mizuno, James M. Moran, Kotaro Moriyama, Cornelia Müller, Alejandro Mus, Gibwa Musoke, Ioannis Myserlis, Andrew Nadolski, Hiroshi Nagai, Neil M. Nagar, Masanori Nakamura, Gopal Narayanan, Iniyan Natarajan, Santiago Navarro Fuentes, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Michael A. Nowak, Junghwan Oh, Hiroki Okino, Gisela N. Ortiz-León, Tomoaki Oyama, Daniel C. M. Palumbo, Georgios Filippos Paraschos, Jongho Park, Harriet Parsons, Nimesh Patel, Ue-Li Pen, Vincent Piétu, Richard Plambeck, Aleksandar PopStefanija, Felix M. Pötzl, Jorge A. Preciado-López, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Bart Ripperda, Freek Roelofs, Alan Rogers, Eduardo Ros, Cristina Romero-Cañizales, Arash Roshanineshat, Helge Rottmann, Alan L. Roy, Ignacio Ruiz, Chet Ruszczyk, Kazi L. J. Rygl, Salvador Sánchez, David Sánchez-Argüelles, Miguel Sánchez-Portal, Mahito Sasada, Kaushik Satapathy, Tuomas Savolainen, F. Peter Schloerb, Jonathan Schonfeld, Karl-Friedrich Schuster, Lijing Shao, Zhiqiang Shen, Des Small, Bong Won Sohn, Jason SooHoo, Kamal Souccar, He Sun, Fumie Tazaki, Alexandra J. Tetarenko, Paul Tiede, Remo P. J. Tilanus, Michael Titus, Pablo Torne, Efthalia Traianou, Tyler Trent, Sascha Trippe, Matthew Turk, Ilse van Bemmel, Huib Jan van Langevelde, Daniel R. van Rossum, Jan Wagner, Derek Ward-Thompson, John Wardle, Jonathan Weintroub, Norbert Wex, Robert Wharton, Kaj Wiik, Gunther Witzel, Michael F. Wondrak, Qingwen Wu, Paul Yamaguchi, André Young, Ken Young, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Shuo Zhang, Guang-Yao Zhao, Shan-Shan Zhao, Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, University of Waterloo, Harvard University, Institute for Advanced Studies, University of Illinois at Urbana-Champaign, Max Planck Institute for Radio Astronomy, University of Arizona, Shanghai Jiao Tong University, University of Southern Denmark, University of Amsterdam, Goethe University Frankfurt, Radboud University Nijmegen, Princeton University, CSIC - Institute of Astrophysics of Andalusia, University of Malaya, Academia Sinica - Institute of Astronomy and Astrophysics, Yale University, Massachusetts Institute of Technology, Fermi National Accelerator Laboratory, East Asian Observatory, Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Science Support Office, Aalto-yliopisto, Aalto University, High Energy Astrophys. & Astropart. Phys (API, FNWI), Georgiev, B., Pesce, D. W., Broderick, A. E., Wong, G. N., Dhruv, V., Wielgus, M., Gammie, C. F., Chan, C. -K., Chatterjee, K., Emami, R., Mizuno, Y., Gold, R., Fromm, C. M., Ricarte, A., Yoon, D., Joshi, A. V., Prather, B., Cruz-Osorio, A., Johnson, M. D., Porth, O., Olivares, H., Younsi, Z., Rezzolla, L., Vos, J., Qiu, R., Nathanail, A., Narayan, R., Chael, A., Anantua, R., Moscibrodzka, M., Akiyama, K., Alberdi, A., Alef, W., Algaba, J. C., Asada, K., Azulay, R., Bach, U., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Baubock, M., Benson, B. A., Bintley, D., Blackburn, L., Blundell, R., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Bustamante, S., Byun, D. -Y., Carlstrom, J. E., Ceccobello, C., Chatterjee, S., Chen, M. -T., Chen, Y., Cheng, X., Cho, I., Christian, P., Conroy, N. S., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Dougal, S., Dzib, S. A., Eatough, R. P., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fuentes, A., Galison, P., Garcia, R., Gentaz, O., Goddi, C., Gomez-Ruiz, A. I., Gomez, J. L., Gu, M., Gurwell, M., Hada, K., Haggard, D., Haworth, K., Hecht, M. H., Hesper, R., Heumann, D., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Impellizzeri, C. M. V., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Kocherlakota, P., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, M., Krichbaum, T. P., Kuo, C. -Y., La Bella, N., Lauer, T. R., Lee, D., Lee, S. -S., Lehner, L., Leung, P. K., Levis, A., Li, Z., Lico, R., Lindahl, G., Lindqvist, M., Lisakov, M., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C. J., Lu, R. -S., Mao, J., Marchili, N., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Menten, K. M., Michalik, D., Mizuno, I., Moran, J. M., Moriyama, K., Muller, C., Mus, A., Musoke, G., Myserlis, I., Nadolski, A., Nagai, H., Nagar, N. M., Nakamura, M., Narayanan, G., Natarajan, I., Fuentes, S. N., Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Oh, J., Okino, H., Ortiz-Leon, G. N., Oyama, T., Palumbo, D. C. M., Paraschos, G. F., Park, J., Parsons, H., Patel, N., Pen, U. -L., Pietu, V., Plambeck, R., Popstefanija, A., Potzl, F. M., Preciado-Lopez, J. A., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Romero-Canizales, C., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruiz, I., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sanchez-Portal, M., Sasada, M., Satapathy, K., Savolainen, T., Schloerb, F. P., Schonfeld, J., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Souccar, K., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Torne, P., Traianou, E., Trent, T., Trippe, S., Turk, M., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wiik, K., Witzel, G., Wondrak, M. F., Wu, Q., Yamaguchi, P., Young, A., Young, K., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhang, S., Zhao, G. -Y., Zhao, S. -S., and Astronomy

Subjects
Accretion, F520, Black holes, Astronomy, F521, Astrophysics::High Energy Astrophysical Phenomena, Stellar accretion, Astronomy and Astrophysics, Galactic center, Magnetohydrodynamics, Space and Planetary Science, Mathematics, Very long baseline interferometry
Abstract

Full list of authors: Georgiev, Boris; Pesce, Dominic W.; Broderick, Avery E.; Wong, George N.; Dhruv, Vedant; Wielgus, Maciek; Gammie, Charles F.; Chan, Chi-kwan; Chatterjee, Koushik ; Emami, Razieh; Mizuno, Yosuke; Gold, Roman; Fromm, Christian M.; Ricarte, Angelo; Yoon, Doosoo; Joshi, Abhishek V.; Prather, Ben; Cruz-Osorio, Alejandro; Johnson, Michael D.; Porth, Oliver; Olivares, Héctor; Younsi, Ziri; Rezzolla, Luciano; Vos, Jesse; Qiu, Richard; Nathanail, Antonios; Narayan, Ramesh; Chael, Andrew; Anantua, Richard; Moscibrodzka, Monika; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom, John E.; Ceccobello, Chiara; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Dougal, Sean; Dzib, Sergio A.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fuentes, Antonio; Galison, Peter; García, Roberto; Gentaz, Olivier; Goddi, Ciriaco; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C. M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Lehner, Luis; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lu, Ru-Sen; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Müller, Cornelia; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Navarro Fuentes, Santiago; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Pötzl, Felix M.; Preciado-López, Jorge A.; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Romero-Cañizales, Cristina; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Argüelles, David; Sánchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Souccar, Kamal; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Torne, Pablo; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wu, Qingwen; Yamaguchi, Paul; Young, André; Young, Ken; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT. © 2022. The Author(s). Published by the American Astronomical Society., The Event Horizon Telescope Collaboration thanks the following organizations and programs: National Science Foundation (awards OISE-1743747, AST-1816420, AST-1716536, AST-1440254, AST-1935980); the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation (although the opinions expressed in this work are those of the author(s) and do not necessarily reflect the views of these foundations); NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555; the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigación y Desarrollo (ANID), Chile via NCN19_058 (TITANs) and Fondecyt 1221421, the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA and the astronomy institutes of the University of Amsterdam, Leiden University, and Radboud University; the Institute for Advanced Study; the China Scholarship Council; Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional Autónoma de México (DGAPA-UNAM, projects IN112417 and IN112820); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the European Research Council for advanced grant "JETSET: Launching, propagation and emission of relativistic jets from binary mergers and across mass scales" (grant No. 884631); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the two Dutch National Supercomputers, Cartesius and Snellius (NWO grant 2021.013); the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; DFG research grant "Jet physics on horizon scales and beyond" (grant No. FR 4069/2-1); Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships, with research at the Flatiron Institute supported by the Simons Foundation; the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP21H01137, JP18H03721, JP18K13594, 18K03709, JP19K14761, 18H01245, 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (103-2119-M-001-010-MY2, 105-2112-M-001-025-MY3, 105-2119-M-001-042, 106-2112-M-001-011, 106-2119-M-001-013, 106-2119-M-001-027, 106-2923-M-001-005, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-001-041, 107-2119-M-110-005, 107-2923-M-001-009, 108-2112-M-001-048, 108-2112-M-001-051, 108-2923-M-001-002, 109-2112-M-001-025, 109-2124-M-001-005, 109-2923-M-001-001, 110-2112-M-003-007-MY2, 110-2112-M-001-033, 110-2124-M-001-007, and 110-2923-M-001-001); the Ministry of Education (MoE) of Taiwan Yushan Young Scholar Program; the Physics Division, National Center for Theoretical Sciences of Taiwan; the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, NASA NuSTAR award 80NSSC20K0645); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2017YFA0402703, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1555365, AST-1614868, AST-1615796, AST-1715061, AST-1716327, AST-2034306); the Natural Science Foundation of China (grants 11650110427, 10625314, 11721303, 11725312, 11873028, 11933007, 11991052, 11991053, 12192220, 12192223); NWO grant No. OCENW.KLEIN.113; a fellowship of China Postdoctoral Science Foundation (2020M671266); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, the Korea Research Fellowship Program: NRF-2015H1D3A1066561, Basic Research Support grant 2019R1F1A1059721, 2022R1C1C1005255); the Dutch Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; and the YCAA Prize Postdoctoral Fellowship. L.M. gratefully acknowledges support from an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award no. AST-1903847. T.K. is supported by MEXT as "Program for Promoting Researches on the Supercomputer Fugaku" (Toward a unified view of the universe: from large-scale structures to planets, JPMXP1020200109) and JICFuS. R.P.D. and I.N. acknowledge funding by the South African Research Chairs Initiative, through the South African Radio Astronomy Observatory (SARAO, grant ID 77948), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Innovation (DSI) of South Africa. We thank the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Spanish Ministerio de Ciencia e Innovación (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21); the University of Pretoria for financial aid in the provision of the new Cluster Server nodes and SuperMicro (USA) for a SEEDING GRANT approved toward these nodes in 2020; the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112); the M2FINDERS project, which has received funding by the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (grant agreement No. 101018682); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (contract 89233218CNA000001); the European Union's Horizon 2020 research and innovation program under grant agreement No. 730562 RadioNet; Shanghai Pilot Program for Basic Research, Chinese Academy of Science, Shanghai Branch (JCYJ-SHFY-2021-013); ALMA North America Development Fund; the Academia Sinica; Chandra DD7-18089X and TM6-17006X; and the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. The XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. The XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www.calculquebec.ca), and Compute Canada (http://www.computecanada.ca). C.C. acknowledges support from the Swedish Research Council (VR). We thank the staff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract No. DE-AC05-00OR22725. We also thank the Center for Computational Astrophysics, National Astronomical Observatory of Japan. Support for this work was also provided by the NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. H.O. and G.M. were supported by Virtual Institute of Accretion (VIA) postdoctoral fellowships from the Netherlands Research School for Astronomy (NOVA). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key Research and Development Program (No. 2017YFA0402700) of China and Natural Science Foundation of China grant 11873028. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. Simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, on the HazelHen cluster at the HLRS in Stuttgart, and on the Pi2.0 and Siyuan Mark-I at Shanghai Jiao Tong University. The computer resources of the Finnish IT Center for Science (CSC) and the Finnish Computing Competence Infrastructure (FCCI) project are acknowledged. J.O. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A3A01086420; 2022R1C1C1005255). We thank Martin Shepherd for the addition of extra features in the Difmap software that were used for the CLEAN imaging results presented in this paper. The computing cluster of Shanghai VLBI correlator supported by the Special Fund for Astronomy from the Ministry of Finance in China is acknowledged. This work was supported by the Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (019H1D3A1A01102564). This research is part of the Frontera computing project at the Texas Advanced Computing Center through the Frontera Large-Scale Community Partnerships allocation AST20023. Frontera is made possible by National Science Foundation award OAC-1818253. This research was carried out using resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy Office of Science. The LMT is a project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30 m telescope on Pico Veleta, Spain, is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany), and IGN (Instituto Geográfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. Support for SPT participation in the EHT is provided by the National Science Foundation through award OPP-1852617 to the University of Chicago. Partial support is also provided by the Kavli Institute of Cosmological Physics at the University of Chicago. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. Support for this work was provided by NASA through the NASA Hubble Fellowship grant No. HST-HF2-51494.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5–26555. Jongho Park acknowledges financial support through the EACOA Fellowship awarded by the East Asia Core Observatories Association, which consists of the Academia Sinica Institute of Astronomy and Astrophysics, the National Astronomical Observatory of Japan, Center for Astronomical Mega-Science, Chinese Academy of Sciences, and the Korea Astronomy and Space Science Institute. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX.

Published
2022
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32. Selective Dynamical Imaging of Interferometric Data

Author

The event horizon telescope collaboration, Pesce, Dominic W., Broderick, Avery E, Wong, George N, Dhruv, Vedant, Wielgus, Maciek, Gammie, Charles F, Chan, Chi-Kwan, Chatterjee, Koushik, Emami, Razieh, Mizuno, Yosuke, Gold, Roman, Fromm, Christian M., Ricarte, Angelo, Yoon, Doosoo, Joshi, Abhishek V, Prather, Ben, Cruz-Osorio, Alejandro, Johnson, Michael D, Port, Oliver, Olivares, Hector, Younsi, Ziri, Rezzolla, Luciano, Vos, Jesse, Wiu, Richard, Nathanail, Antonios, Narayan, Ramesh, Chael, Andrew, Anantua, Richard, Moscibrodzka, Monika, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Asada, Keiichi, Azulay, Rebecca, Li, Yan-Rong, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Boland, Wilfred, Benson, Bradford A, Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Bouman, Katherine L, Bower, Geoffery C, Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D, Brissenden, Roger, Brtizen, Silke, Broguiere, Domonique, Bronzwaer, Thomas, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E, MacDonald, Nicholas R, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Feryal, Zel, Conway, John E, Cordes, James M, Crawford, Thomas M, Crew, Geoffrey B, Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelcia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Psaltis, Dimitrios, Doeleman, Sheperd S, Rose, Mel, Toma, Kenji, Eatough, Ralph P, Falcke, Heino, Farah, Joseph, Fish, Vincent L, Fomalont, Ed, Ford, H. Alyson, Fraga-Encinas, Raquel, Moriyama, Kotaro, Friberg, Per, Fuentes, Antonio, Galison, Peter, Garcia, Roberto, Gentaz, Olivier, Goddi, Ciriaco, Gómez-Ruiz, Arturo L, Gómez, José L, Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Hecht, Michael H, Hesper, Ronald, Ho, Luis C, Ho, Paul, Honma, Mareki, Huang, Chih-Wei L, Huang, Lei, Hughes, David H, Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J, Jannuzi, Buell T, Janssen, Michael, Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K, Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kofuji, Yutaro, Koch, Patrick M, Koyama, Shoko, Kramer, Carsten, Kramer, Michael, Krichbaum, Thomas P, Kuo, Cheng-Yu, Lauer, Tod R, Lee, Sang-Sung, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P, Loinard, Laurent, Lonsdale, Colin J, Lu, Ru-Sen, Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P, Marscher, Alan P, Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D, Menten, Karl M, Medeiros, Lia, Mizuno, Izumi, Moran, James M, Muller, Cornelia, Mus Mejas, Alejandro, Musoke, Gibwa, Nagai, Hiroshi, Nagar, Neil M, Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Fuentes, Santiago Navarro, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A, Okino, Hiroki, Ortiz-Leon, Gisela N, Oyama, Tomoaki, Palumbo, Daniel C M, Porth, Oliver, Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Pötzl, Felix M, Preciado-Lopez, Jorge A, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G, Raymond, Alexander W, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L, Ruszczyk, Chet, Rygl, Kazi L J, Sanchez, Salvador, Sánchez-Argüelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J, Tiede, Paul, Tilanus, Remo P J, Titus, Michael, Torne, Pablo, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Bemmel, Isle van, van Langevelde, Huib Jan, van Rossum, Daniel R, Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wiik, Kaj, Wu, Qingwen, Young, Andre, Young, Ken, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Yao, Zhao, Guang-Yao, Zhao, Shan-Shan, Farah, J., Galison, P., Akiyama, K., Bouman, K. L., Bower, G. C., Chael, A., Fuentes, A., Gomez, J. L., Honma, M., Johnson, M. D., Kofuji, Y., Marrone, D. P., Moriyama, K., Narayan, R., Pesce, D. W., Tiede, P., Wielgus, M., Zhao, G. -Y., Alberdi, A., Alef, W., Algaba, J. C., Anantua, R., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Benson, B. A., Bintley, D., Blackburn, L., Blundell, R., Boland, W., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Bustamente, S., Byun, D. -Y., Carlstrom, J. E., Chan, C. -K., Chatterjee, K., Chatterjee, S., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gammie, C. F., Garc'A, R., Gentaz, O., Goddi, C., Gold, R., Gomez-Ruiz, A. I., Gu, M., Gurwell, M., Hada, K., Haggard, D., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, M., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Levis, A., Li, Y. -R., Li, Z., Lico, R., Lindahl, G., Lindqvist, M., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Marchili, N., Markoff, S., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, I., Mizuno, Y., Moran, J. M., Moscibrodzka, M., Muller, C., Mejas, A. M., Musoke, G., Nagai, H., Nagar, N. M., Nakamura, M., Narayanan, G., Natarajan, I., Nathanail, A., Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Park, J., Patel, N., Pen, U. -L., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Potzl, F. M., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Sun, H., Tazaki, F., Tetarenko, A. J., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Traianou, E., Trent, T., Trippe, S., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wiik, K., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, S. -S., Ministerio de Ciencia e Innovación (España), European Commission, European Research Council, National Science Foundation (US), Gordon and Betty Moore Foundation, Las Cumbres Observatory Global Telescope Network, Harvard University, Academia Sinica - Institute of Astronomy and Astrophysics, Princeton University, CSIC - Institute of Astrophysics of Andalusia, National Astronomical Observatory of Japan, University of Arizona, Massachusetts Institute of Technology, University of Waterloo, University of Malaya, Universidad de Valencia, Fermi National Accelerator Laboratory, East Asian Observatory, Nederlandse Onderzoekschool voor Astronomie, McGill University, Institut de Radio Astronomie Millimétrique, Radboud University Nijmegen, University of Massachusetts, Korea Astronomy and Space Science Institute, University of Chicago, University of Amsterdam, Universidad de Concepción, Department of Electronics and Nanoengineering, Science Support Office, Aalto-yliopisto, Aalto University, High Energy Astrophys. & Astropart. Phys (API, FNWI), Kapteyn Astronomical Institute, and Astronomy

Subjects
Interferometry, Space and Planetary Science, F520, F521, Astrophysical black holes, Astronomy, Astronomy and Astrophysics, Very long baseline interferometry, Aperture synthesis
Abstract

Full list of authors: Farah, Joseph; Galison, Peter; Akiyama, Kazunori; Bouman, Katherine L.; Bower, Geoffrey C.; Chael, Andrew; Fuentes, Antonio; Gómez, José L.; Honma, Mareki; Johnson, Michael D.; Kofuji, Yutaro; Marrone, Daniel P.; Moriyama, Kotaro; Narayan, Ramesh; Pesce, Dominic W.; Tiede, Paul; Wielgus, Maciek; Zhao, Guang-Yao; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamente, Sandra; Byun, Do-Young; Carlstrom, John E.; Chan, Chi-kwan; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Gammie, Charles F.; Garc'a, Roberto; Gentaz, Olivier; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moscibrodzka, Monika; Müller, Cornelia; Mejas, Alejandro Mus; Musoke, Gibwa; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; zel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wiik, Kaj; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Shan-Shan; Event Horizon Telescope Collaboration.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., Recent developments in very long baseline interferometry (VLBI) have made it possible for the Event Horizon Telescope (EHT) to resolve the innermost accretion flows of the largest supermassive black holes on the sky. The sparse nature of the EHT's (u, v)-coverage presents a challenge when attempting to resolve highly time-variable sources. We demonstrate that the changing (u, v)-coverage of the EHT can contain regions of time over the course of a single observation that facilitate dynamical imaging. These optimal time regions typically have projected baseline distributions that are approximately angularly isotropic and radially homogeneous. We derive a metric of coverage quality based on baseline isotropy and density that is capable of ranking array configurations by their ability to produce accurate dynamical reconstructions. We compare this metric to existing metrics in the literature and investigate their utility by performing dynamical reconstructions on synthetic data from simulated EHT observations of sources with simple orbital variability. We then use these results to make recommendations for imaging the 2017 EHT Sgr A* data set. © 2022. The Author(s). Published by the American Astronomical Society., We thank the National Science Foundation (awards OISE-1743747, AST-1816420, AST-1716536, AST-1440254, AST-1935980) and the Gordon and Betty Moore Foundation (GBMF-5278) for financial support of this work. This work was supported in part by the Black Hole Initiative, which is funded by grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation to Harvard University. Support for this work was also provided by the NASA Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. The Event Horizon Telescope Collaboration thanks the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigacin y Desarrollo (ANID), Chile via NCN19058 (TITANs) and Fondecyt 3190878, the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, the NL astronomy research network NOVA and the astronomy institutes of the University of Amsterdam, Leiden University, and Radboud University; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccin General de Asuntos del Personal Acadmico-Universidad Nacional Autnoma de Mxico (DGAPA-UNAM, projects IN112417 and IN112820); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22; the European Research Council for advanced grant "JETSET: Launching, propagation and emission of relativistic jets from binary mergers and across mass scales" (grant No. 884631); the Gordon and Betty Moore Foundation (grant GBMF-3561); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the two Dutch National Supercomputers, Cartesius and Snellius (NWO grant 2021.013); the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; Joint Princeton/Flatiron and Joint Columbia/Flatiron Postdoctoral Fellowships, with research at the Flatiron Institute being supported by the Simons Foundation; the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP21H01137, JP18H03721, 18K03709, 18H01245, 25120007); the Malaysian Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (103-2119-M-001-010-MY2, 105-2112-M-001-025-MY3, 105-2119-M-001-042, 106-2112-M-001-011, 106-2119-M-001-013, 106-2119-M-001-027, 106-2923-M-001-005, 107-2119-M-001-017, 107-2119-M-001-020, 107-2119-M-001-041, 107-2119-M-110-005, 107-2923-M-001-009, 108-2112-M-001-048, 108-2112-M-001-051, 108-2923-M-001-002, 109-2112-M-001-025, 109-2124-M-001-005, 109-2923-M-001-001, 110-2112-M-003-007-MY2, 110-2112-M-001-033, 110-2124-M-001-007, and 110-2923-M-001-001); the Ministry of Education (MoE) of Taiwan Yushan Young Scholar Program; the Physics Division, National Center for Theoretical Sciences of Taiwan; the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, NASA NuSTAR award 80NSSC20K0645); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1555365, AST-1615796, AST-1715061, AST-1716327, AST-1903847, AST-2034306); the Natural Science Foundation of China (grants 11650110427, 10625314, 11721303, 11725312, 11933007, 11991052, 11991053); NWO grant No. OCENW.KLEIN.113; a fellowship of China Postdoctoral Science Foundation (2020M671266); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807; the Korea Research Fellowship Program: NRF-2015H1D3A1066561, Basic Research Support Grant 2019R1F1A1059721); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at the Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Spanish Ministerio de Ciencia e Innovacin (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofsica de Andaluca (SEV-2017-0709); the Toray Science Foundation; the Consejera de Economa, Conocimiento, Empresas y Universidad of the Junta de Andaluca (grant P18-FR-1769), the Consejo Superior de Investigaciones Cientficas (grant 2019AEP112); the M2FINDERS project, which has received funding by the European Research Council (ERC) under the European Unions Horizon 2020 Research and Innovation Programme (grant agreement No. 101018682); the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (contract 89233218CNA000001); the European Unions Horizon 2020 research and innovation program under grant agreement No. 730562 RadioNet; Shanghai Pilot Program for Basic Research, Chinese Academy of Science, Shanghai Branch (JCYJ-SHFY-2021-013); ALMA North America Development Fund; the Academia Sinica; Chandra DD7-18089X and TM6-17006X; and the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. The XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. The XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www.calculquebec.ca), and Compute Canada (http://www.computecanada.ca). C.C. acknowledges support from the Swedish Research Council (VR). We thank the staff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. Hector Olivares and Gibwa Musoke were supported by Virtual Institute of Accretion (VIA) postdoctoral fellowships from the Netherlands Research School for Astronomy (NOVA). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. Simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, on the HazelHen cluster at the HLRS in Stuttgart, and on the Pi2.0 and Siyuan Mark-I at Shanghai Jiao Tong University. The computer resources of the Finnish IT Center for Science (CSC) and the Finnish Computing Competence Infrastructure (FCCI) project are acknowledged. Junghwan Oh was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A3A01086420). We thank Martin Shepherd for the addition of extra features in the Difmap software that were used for the CLEAN imaging results presented in this paper. The computing cluster of Shanghai VLBI correlator supported by the Special Fund for Astronomy from the Ministry of Finance in China is acknowledged. The LMT is a project operated by the Instituto Nacional de Astrofisica, Optica, y Electronica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30 m telescope on Pico Veleta, Spain, is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck- Gesellschaft, Germany), and IGN (Instituto Geogrfico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. Support for SPT participation in the EHT is provided by the National Science Foundation through award OPP-1852617 to the University of Chicago. Partial support is also provided by the Kavli Institute of Cosmological Physics at the University of Chicago. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. Support for this work was provided by NASA through the NASA Hubble Fellowship grant No. HST-HF2-51494.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5–26555. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We thank J. Delgado for helpful discussions and feedback.

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2022
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33. Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

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Masanori Nakamura, R. Shang, Abelardo Moralejo, A. Rugliancich, Marina Manganaro, Jun Liu, Monika Moscibrodzka, Andreas Specovius, V. Ramakrishnan, S. O'Brien, Michal Ostrowski, Luis C. Ho, Sera Markoff, D. Depaoli, I. Jung-Richardt, Manel Errando, Chiara Righi, S. Panny, Toshiaki Inada, Alexandra J. Tetarenko, Daniela Dorner, Norbert Wex, Nimesh A. Patel, Olivier Hervet, C. Arcaro, Alasdair E. Gent, Yu Wun Wong, Gaia Vanzo, Pierre Brun, Konstancja Satalecka, Stefan Funk, Lorenzo Bellizzi, Michael Lindqvist, Michele Doro, Felix Jankowsky, P. Kaaret, Nicholas R. MacDonald, Lang Cui, P. Temnikov, S. Patel, Sabrina Einecke, Manuel Artero, E. Moretti, Hope Boyce, M. Gaug, Charles F. Gammie, Iryna Lypova, Gisela N. Ortiz-León, Felix Aharonian, Colin J. Lonsdale, Buell T. Jannuzi, Gavin Rowell, M. Bryan, Yvonne Becherini, Aleksandar Popstefanija, M. Pohl, A. Marcowith, Jean-Pierre Ernenwein, H. Alyson Ford, Wystan Benbow, Karen E. Williamson, Daryl Haggard, Hambeleleni Ndiyavala, Tod R. Lauer, Arnaud Mares, Chaitanya Priyadarshi, Michael Punch, Helge Rottmann, J. Zorn, D. Dominis Prester, Bernd Schleicher, M. Minev, Hector Olivares, Ciriaco Goddi, S. Pita, J. Herrera, Alessia Spolon, Léa Jouvin, Na Wang, G. Martí-Devesa, Tomohiko Oka, Kirsty Feijen, E. Do Souto Espiñeira, Ralph Eatough, Johannes Veh, Stefano Gabici, Tomislav Terzić, D. Glawion, Gilles Fontaine, Bradford Benson, C. B. Rulten, Jenni Jormanainen, Jason SooHoo, Michael Titus, Jose Miguel Delgado, Marcos López-Moya, Freek Roelofs, Wlodek Bednarek, M. Lundy, Richard Anantua, Alessandra Lamastra, P. T. Reynolds, Vassil Verguilov, M. Lemoine-Goumard, G. Fichet de Clairfontaine, L. Di Venere, Michael Kreter, Jose Miguel Miranda, Alan L. Roy, Yating Chai, A. López-Oramas, M. Tluczykont, Jacek Niemiec, R. Konno, Tyler Trent, Olaf Reimer, Heino Falcke, Amanpreet Kaur, M. Panter, Narek Sahakyan, Kasper B. Schmidt, A. Carosi, K. Egberts, L. Maraschi, Stefan Cikota, V. Joshi, Koji Noda, Elisa Bernardini, Ye-Fei Yuan, Garrett K. Keating, Fumie Tazaki, Pawel Gliwny, M. Vazquez Acosta, Nicola Giglietto, M. Capasso, Vincent Piétu, Satoshi Fukami, Roman Gold, Elina Lindfors, Satoki Matsushita, A. Lemiere, F. Eichhorn, U. Katz, Yoshinori Yonekura, N. Shafi, Natalia Żywucka, Michael Kramer, M. Palatiello, Daniel Mazin, Samuel Timothy Spencer, Victoria Moreno, Oliver Porth, Julian Sitarek, Kazi L.J. Rygl, Wen Ping Lo, Geoffrey C. Bower, Ilje Cho, S. Fegan, Samuel Zouari, J. M. Paredes, V. Fallah Ramazani, Thomas Murach, Jim Hinton, R. J. White, F. Leone, S. Loporchio, M. de Naurois, Ed Fomalont, Bart Ripperda, Dominique Broguiere, J. Becerra González, Joseph R. Farah, Q. Feng, Andreas Quirrenbach, Taehyun Jung, C. Trichard, Masahiro Teshima, Domenico Tiziani, D. Malyshev, Richard Plambeck, Lynn D. Matthews, Avery E. Broderick, S. Kumar, T. J. Williamson, M. K. Daniel, Sylvia Zhu, P. J. Meintjes, Tjark Miener, Jodi Christiansen, Roger Brissenden, S. Sailer, Dmitry Khangulyan, David Paneque, Thomas P. Krichbaum, Sergey S. Savchenko, Angelo Ricarte, Riaan Steenkamp, T. Chand, J. Dyks, Francesco Dazzi, V. Baghmanyan, Zorawar Wadiasingh, Kazunori Akiyama, Stefan Ohm, C. Levy, Giovanna Ferrara, Makoto Inoue, Jhilik Majumdar, Nobuyuki Sakai, Dieter Horns, Jorge A. Preciado-López, Cornelia Müller, G. Hermann, Regis Terrier, A. J. Chromey, Dominic W. Pesce, Felix M. Pötzl, Mark Gurwell, Alejandro Cruz-Osorio, Ivan Marti-Vidal, Ben Prather, Tom Armstrong, Jongho Park, Matteo Cerruti, Ziri Younsi, Amy Furniss, Chih-Wei Locutus Huang, Lijing Shao, A. Djannati-Ataï, Shoko Koyama, D. Gottschall, P. Vincent, A. Brill, Kenji Toma, Antonios Nathanail, M. Nievas-Rosillo, M. Seglar-Arroyo, C. Delgado Mendez, Mahito Sasada, G. Busetto, Maciek Wielgus, Marcos Santander, Doosoo Yoon, D. A. Sanchez, Hiroki Okino, Christo Venter, Christiaan D. Brinkerink, James Ryan, S. Mićanović, Raquel Fraga-Encinas, Mark G. Rawlings, G. H. Sembroski, G. Principe, Xiang Liu, Karl Friedrich Schuster, Ronald Hesper, L. Sun, Ciro Bigongiari, Ramesh Narayan, M. Strzys, L. Mohrmann, Daniel R. van Rossum, Y. Ohtani, Wu Jiang, Luciano Rezzolla, Nu. Komin, V. A. Acciari, Katherine L. Bouman, Jürgen Besenrieder, Clemens Hoischen, A. A. Zdziarski, Antonio Tutone, Hung Yi Pu, A. Arbet Engels, J.-P. Lenain, A. De Angelis, Tomoya Hirota, R. J. García López, Carlo Romoli, Werner Hofmann, Tuomas Savolainen, Neil M. Nagar, Minfeng Gu, M. Karjalainen, Vitaly Neustroev, A. N. Otte, John F. C. Wardle, Tomoaki Oyama, Jongsoo Kim, Monica Barnard, J. Otero-Santos, R. D. Parsons, Pierre Christian, A. Priyana Noel, A. S. Seyffert, Shami Chatterjee, E. O. Angüner, David A. Green, Ramesh Karuppusamy, Zhiyuan Li, J. Devin, Dominik Elsaesser, F. Giordano, Santiago Ubach, Michael A. Nowak, Y. Kobayashi, F. Di Pierro, Iniyan Natarajan, A. Zech, M. Garczarczyk, Dmitriy Kostunin, Michael Janssen, Giacomo Bonnoli, Mariafelicia De Laurentis, Kuo Liu, G. Emery, Yutaro Kofuji, Antxon Alberdi, Marco Toliman Lucchini, R. A. Ong, Catherine Boisson, Daniel C. M. Palumbo, Stefan Klepser, Stefano Covino, Motoki Kino, Daniel Kerszberg, C. Armand, Maria Haupt, D. Zarić, K. Pfrang, R. López-Coto, M. Zacharias, Jae-Young Kim, Sheperd S. Doeleman, U. Barres de Almeida, Pratik Majumdar, M. V. Fonseca, Mosè Mariotti, G. Lamanna, Alexander Hahn, Sidika Merve Colak, R. J. Tuffs, B. Bi, Juan-Carlos Algaba, L. Oakes, D. Jankowsky, Y. Kajiwara, R. Marx, Bošnjak, John E. Barrett, Kotaro Niinuma, F. D'Ammando, Qingwen Wu, A. Yusafzai, Christian M. Fromm, Chi-kwan Chan, B. De Lotto, M. Kertzman, Manuela Mallamaci, H. Prokoph, Tadayuki Takahashi, Damir Lelas, Victor Doroshenko, E. Kasai, Lea Heckmann, Bong Won Sohn, Francesco Gabriele Saturni, Shiro Ikeda, T. Vuillaume, Laurent Loinard, G. Maurin, M. Füßling, Martin Will, Yi Chen, Gianluca Giavitto, Remo P. J. Tilanus, M. Spir-Jacob, Alessandro Montanari, Thomas Lohse, Tihomir Surić, J. van Scherpenberg, Per Friberg, He Sun, Luca Tosti, Kiyoaki Wajima, E. Ruiz-Velasco, Thomas Bylund, M. Balokovic, Feng Yuan, S. Nozaki, Mischa Breuhaus, Peter Galison, Y. A. Gallant, L. Olivera-Nieto, Dorota Sobczyńska, Maria-Isabel Bernardos, R. Rauth, Izumi Mizuno, Vincent L. Fish, S. G. Jorstad, Tomoki Saito, Giovanni Ceribella, Jacques Muller, J. P. Finley, Stefano Ansoldi, Boris Georgiev, Marcello Giroletti, Arturo I. Gómez-Ruiz, Karl M. Menten, Aristeidis Noutsos, P. deWilt, Junhan Kim, Alejandro Mus Mejías, Q. Remy, Dong-Jin Kim, P. G. Prada Moroni, Robert Wharton, Riccardo Paoletti, R. R. Prado, Zhi-Qiang Shen, S. Paiano, S. Chandra, Andrés Baquero, Anna Barnacka, Lucy Fortson, Wrijupan Bhattacharyya, Marc Ribó, E. de Ona Wilhelmi, Paul T. P. Ho, Yan-Rong Li, Derek Ward-Thompson, M. Scalici, G. Maneva, Constantin Steppa, Dimitrios Psaltis, A.M. Taylor, J. Damascene Mbarubucyeye, Daniel P. Marrone, Karl Mannheim, W. Boland, P. Morris, D. A. Prokhorov, M. Mohamed, Katsuaki Asano, Gernot Maier, Kotaro Moriyama, H. Odaka, M. Büchele, E. Pueschel, Kazuyoshi Nishijima, Christopher J. Duffy, H. M. Schutte, Camilla Maggio, Mark Kettenis, V. D'Elia, Saverio Lombardi, Ramprasad Rao, Ivica Puljak, R. Mirzoyan, V. Sahakian, Guang Yao Zhao, Adrian Biland, F. Werner, Rafal Moderski, Olivier Gentaz, Ullrich Schwanke, James M. Moran, S. Komossa, Yuzhu Cui, A. Jiménez-Rosales, Arash Roshanineshat, S. Ventura, Lindy Blackburn, David J. James, G. Hughes, Hidetoshi Kubo, Mansour Karami, José L. Gómez, P. Reichherzer, Davit Zargaryan, Paul Tiede, Koushik Chatterjee, Chunchong Ni, Roger Deane, Axel Donath, J. Rico, A. W. Chen, A. Fiasson, Jun Yi Koay, T. B. Humensky, Satoko Sawada-Satoh, Isak Delberth Davids, Alan P. Marscher, Alan E. E. Rogers, Rebecca Azulay, Kazuma Ishio, Paul M. Chesler, D. M. Strom, Carlo Vigorito, Marek Jamrozy, G. Pühlhofer, M. de Bony de Lavergne, Roberta Zanin, T. Schweizer, Elisa Prandini, Helene Sol, Rodolfo Carosi, M. Hörbe, T. Tavernier, Mareki Honma, M. Holler, Gordon T. Richards, Armelle Jardin-Blicq, Paolo Marchegiani, Sang-Sung Lee, D. Huber, Ashot Chilingarian, Nikola Godinovic, F. Ait Benkhali, Jason Dexter, Do-Young Byun, Anton Dmytriiev, Massimo Persic, Alicia Fattorini, L. Dirson, Cosimo Nigro, E. Roache, Sargis Gasparyan, S. Schwemmer, Sara Issaoun, Jessica Dempsey, Andrea Santangelo, Włodek Kluźniak, Mel Rose, Huib Jan van Langevelde, D. J. van der Walt, Elisabetta Liuzzo, A. Stamerra, John Hoang, Michelle Tsirou, Wolfgang Rhode, Tomohisa Kawashima, L. A. Antonelli, Carolin Wunderlich, Keiichi Asada, David A. Williams, Joachim Hahn, P. Moriarty, T. M. Crawford, P. Da Vela, L. Rinchiuso, E. Molina, F. Peter Schloerb, Lovro Pavletić, S. Steinmassl, Des Small, Christoph Deil, Stefano Menchiari, Dan Bintley, K. Nakashima, Alice Donini, David H. Hughes, Heinrich J. Völk, Mohanraj Senniappan, K. A. Farrell, M. Renaud, J. A. Barrio, Miriam Lucio Martinez, Rachel Simoni, P. T. O'Brien, E. Colombo, V. Barbosa Martins, M. Orienti, Efthalia Traianou, Lluis Font, B. Machado de Oliveira Fraga, Y. Suda, J. Neilsen, John Conway, Eduardo Ros, Gibwa Musoke, Tarek M. Hassan, J. Bolmont, A. Sinha, Halim Ashkar, M.-H. Grondin, Daniel Nieto, Lab Saha, Fabrizio Tavecchio, Hyunwook Ro, Michael H. Hecht, Markus Böttcher, Antonio Fuentes, Simone Mender, Moritz Hütten, Ue-Li Pen, Yosuke Mizuno, Gopal Narayanan, Lei Huang, H. Abdalla, M. A. Kastendieck, Nicola Marchili, I. Snidaric, S. Sánchez, G. Vasileiadis, Kari Nilsson, Alexander W. Raymond, Greg Lindahl, Gregory Desvignes, Sascha Trippe, Sanae Inoue, Giacomo D'Amico, W. Jin, B. van Soelen, Andrew Chael, Anne Kathrin Baczko, Shunsuke Sakurai, L. Giunti, A. Nayerhoda, Walter Alef, Jamie Holder, Stefano Truzzi, Pablo Peñil, M. J. Lang, Francois Brun, Frank M. Rieger, V. Vitale, George N. Wong, Jirong Mao, S. Caroff, J. 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Katarzyński, Roberto Neri, The EHT MWL Science Working Group, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de RadioAstronomía Milimétrica (IRAM), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Groupe de Physique des Solides (GPS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL), Event Horizon Telescope, Fermi-LAT, H.E.S.S., MAGIC, VERITAS, EAVN, High Energy Astrophys. & Astropart. Phys (API, FNWI), API Other Research (FNWI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Algaba, Jc, Anczarski, J, Asada, K, Balokovic, M, Chandra, S, Cui, Yz, Falcone, Ad, Giroletti, M, Goddi, C, Hada, K, Haggard, D, Jorstad, S, Kaur, A, Kawashima, T, Keating, G, Kim, Jy, Kino, M, Komossa, S, Kravchenko, Ev, Krichbaum, Tp, Lee, S, Lu, R, Lucchini, M, Markoff, S, Neilsen, J, Nowak, Ma, Park, J, Principe, G, Ramakrishnan, V, Reynolds, Mt, Sasada, M, Savchenko, S, Williamson, Ke, Longo, F, Et, Al., University of Michigan, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Algaba, J. C., Anczarski, J., Asada, K., Balokovic, M., Chandra, S., Cui, Y. -Z., Falcone, A. D., Giroletti, M., Goddi, C., Hada, K., Haggard, D., Jorstad, S., Kaur, A., Kawashima, T., Keating, G., Kim, J. -Y., Kino, M., Komossa, S., Kravchenko, E. V., Krichbaum, T. P., Lee, S. -S., Lu, R. -S., Lucchini, M., Markoff, S., Neilsen, J., Nowak, M. A., Park, J., Principe, G., Ramakrishnan, V., Reynolds, M. T., Sasada, M., Savchenko, S. S., Williamson, K. E., Akiyama, K., Alberdi, A., Alef, W., Anantua, R., Azulay, R., Baczko, A. -K., Ball, D., Barrett, J., Bintley, D., Benson, B. A., Blackburn, L., Blundell, R., Boland, W., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Chesler, P. M., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Farah, J., Fish, V. L., Fomalont, E., Ford, H. A., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Gold, R., Gomez, J. L., Gomez-Ruiz, A. I., Gu, M., Gurwell, M., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jung, T., Karami, M., Karuppusamy, R., Kettenis, M., Kim, D. -J., Kim, J., Koay, J. Y., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C. -Y., Lauer, T. R., Levis, A., Li, Y. -R., Li, Z., Lindqvist, M., Lico, R., Lindahl, G., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Macdonald, N. R., Mao, J., Marchili, N., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Musoke, G., Mejias, A. M., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Potzl, F. M., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Ward-Thompson, D., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G. -Y., Zhao, S. -S., D'Ammando, F., Orienti, M., Abdalla, H., Adam, R., Aharonian, F., Benkhali, F. A., Anguner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Barbosa Martins, V., Barnacka, A., Barnard, M., Becherini, Y., Berge, D., Bernlohr, K., Bi, B., Bottcher, M., Boisson, C., Bolmont, J., De Bony De Lavergne, M., Breuhaus, M., Brun, F., Brun, P., Bryan, M., Buchele, M., Bulik, T., Bylund, T., Caroff, S., Carosi, A., Casanova, S., Chand, T., Chen, A., Cotter, G., Curylo, M., Damascene Mbarubucyeye, J., Davids, I. D., Davies, J., Deil, C., Devin, J., Dewilt, P., Dirson, L., Djannati-Atai, A., Dmytriiev, A., Donath, A., Doroshenko, V., Duffy, C., Dyks, J., Egberts, K., Eichhorn, F., Einecke, S., Emery, G., Ernenwein, J. -P., Feijen, K., Fegan, S., Fiasson, A., De Clairfontaine, G. F., Fontaine, G., Funk, S., Fussling, M., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Hahn, J., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Horbe, M., Horns, D., Huber, D., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jardin-Blicq, A., Joshi, V., Jung-Richardt, I., Kasai, E., Kastendieck, M. A., Katarzynski, K., Katz, U., Khangulyan, D., Khelifi, B., Klepser, S., Kluzniak, W., Komin, N., Konno, R., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P., Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Marti-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Moderski, R., Mohamed, M., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Nayerhoda, A., De Naurois, M., Ndiyavala, H., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Ohm, S., Olivera-Nieto, L., De Ona Wilhelmi, E., Ostrowski, M., Panter, M., Panny, S., Parsons, R. D., Peron, G., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Noel, A. P., Prokhorov, D. A., Prokoph, H., Puhlhofer, G., Punch, M., Quirrenbach, A., Rauth, R., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Rieger, F., Rinchiuso, L., Romoli, C., Rowell, G., Rudak, B., Ruiz-Velasco, E., Sahakian, V., Sailer, S., Sanchez, D. A., Santangelo, A., Sasaki, M., Scalici, M., Schutte, H. M., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, L., Sun, L., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Tiziani, D., Tluczykont, M., Tomankova, L., Trichard, C., Tsirou, M., Tuffs, R., Uchiyama, Y., Van Der Walt, D. J., Van Eldik, C., Van Rensburg, C., Van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Volk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Y. W., Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zorn, J., Zouari, S., Zywucka, N., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. A., Artero, M., Asano, K., Baack, D., Babic, A., Baquero, A., De Almeida, U. B., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovic, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jimenez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez-Coto, R., Lopez-Moya, M., Lopez-Oramas, A., Loporchio, S., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Menchiari, S., Mender, S., Micanovic, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletic, L., Penil, P., Perennes, C., Persic, M., Moroni, P. G. P., Prandini, E., Priyadarshi, C., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zaric, D., Adams, C. B., Benbow, W., Brill, A., Capasso, M., Christiansen, J. L., Chromey, A. J., Daniel, M. K., Errando, M., Farrell, K. A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Gent, A., Giuri, C., Hassan, T., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Jin, W., Kaaret, P., Kertzman, M., Kieda, D., Kumar, S., Lang, M. J., Lundy, M., Maier, G., Moriarty, P., Mukherjee, R., Nieto, D., Nievas-Rosillo, M., O'Brien, S., Ong, R. A., Otte, A. N., Patel, S., Pfrang, K., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Richards, G. T., Roache, E., Rulten, C., Ryan, J. L., Santander, M., Sembroski, G. H., Shang, R., Weinstein, A., Williams, D. A., Williamson, T. J., Hirota, T., Cui, L., Niinuma, K., Ro, H., Sakai, N., Sawada-Satoh, S., Wajima, K., Wang, N., Liu, X., Yonekura, Y., German Research Foundation, Istituto Nazionale di Fisica Nucleare, Swiss National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Department of Atomic Energy (India), University of Tokyo, Japan Society for the Promotion of Science, Ministry of Education and Scientific Research (Romania), Academy of Finland, La Caixa, Croatian Science Foundation, Generalitat de Catalunya, Polish National Agency for Academic Exchange, University of Rijeka, Department of Energy (US), Smithsonian Institution, Astronomy, and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
Accretion, 010504 meteorology & atmospheric sciences, Astronomy, Flux, Astrophysics, 7. Clean energy, 01 natural sciences, Active galactic nuclei, Radio cores, Low-luminosity active galactic nuclei, High energy astrophysics, Astrophysical black holes, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, astro-ph.HE, Radio core, Accretion (meteorology), 520 Astronomie und zugeordnete Wissenschaften, Low-luminosity, active galactic nuclei, Astrophysical black hole, astro-ph.CO, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, High-energy astronomy, astro-ph.GA, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, F500, Astrophysics::Cosmology and Extragalactic Astrophysics, High energy astrophysic, 0103 physical sciences, Very-long-baseline interferometry, ddc:530, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Event Horizon Telescope, Supermassive black hole, Astronomy and Astrophysics, 530 Physik, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ddc:520, HESS - Abteilung Hinton, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Full list of authors: EHT MWL Science Working Group; Algaba, J. C.; Anczarski, J.; Asada, K.; Baloković, M.; Chandra, S.; Cui, Y. -Z.; Falcone, A. D.; Giroletti, M.; Goddi, C.; Hada, K.; Haggard, D.; Jorstad, S.; Kaur, A.; Kawashima, T.; Keating, G.; Kim, J. -Y.; Kino, M.; Komossa, S.; Kravchenko, E. V.; Krichbaum, T. P.; Lee, S. -S.; Lu, R. -S.; Lucchini, M.; Markoff, S.; Neilsen, J.; Nowak, M. A.; Park, J.; Principe, G.; Ramakrishnan, V.; Reynolds, M. T.; Sasada, M.; Savchenko, S. S.; Williamson, K. E.; Event Horizon Telescope Collaboration; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Anantua, Richard; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Barrett, John; Bintley, Dan; Benson, Bradford A.; Blackburn, Lindy; Blundell, Raymond; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chan, Chi-Kwan; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Chesler, Paul M.; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Davelaar, Jordy; de Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Ed; Ford, H. Alyson; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Gold, Roman; Gómez, José L.; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kettenis, Mark; Kim, Dong-Jin; Kim, Jongsoo; Kim, Junhan; Koay, Jun Yi; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Lindahl, Greg; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Musoke, Gibwa; Mejías, Alejandro Mus; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; Popstefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; Soohoo, Jason; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan; Fermi Large Area Telescope Collaboration; Principe, G.; Giroletti, M.; D'Ammando, F.; Orienti, M.; H. E. S. S. Collaboration; Abdalla, H.; Adam, R.; Aharonian, F.; Benkhali, F. Ait; Angüner, E. O.; Arcaro, C.; Armand, C.; Armstrong, T.; Ashkar, H.; Backes, M.; Baghmanyan, V.; Barbosa Martins, V.; Barnacka, A.; Barnard, M.; Becherini, Y.; Berge, D.; Bernlöhr, K.; Bi, B.; Böttcher, M.; Boisson, C.; Bolmont, J.; de Lavergne, M. De Bony; Breuhaus, M.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Bylund, T.; Caroff, S.; Carosi, A.; Casanova, S.; Chand, T.; Chen, A.; Cotter, G.; Curyło, M.; Damascene Mbarubucyeye, J.; Davids, I. D.; Davies, J.; Deil, C.; Devin, J.; Dewilt, P.; Dirson, L.; Djannati-Ataï, A.; Dmytriiev, A.; Donath, A.; Doroshenko, V.; Duffy, C.; Dyks, J.; Egberts, K.; Eichhorn, F.; Einecke, S.; Emery, G.; Ernenwein, J. -P.; Feijen, K.; Fegan, S.; Fiasson, A.; de Clairfontaine, G. Fichet; Fontaine, G.; Funk, S.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Giavitto, G.; Giunti, L.; Glawion, D.; Glicenstein, J. F.; Gottschall, D.; Grondin, M. -H.; Hahn, J.; Haupt, M.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holch, T. L.; Holler, M.; Hörbe, M.; Horns, D.; Huber, D.; Jamrozy, M.; Jankowsky, D.; Jankowsky, F.; Jardin-Blicq, A.; Joshi, V.; Jung-Richardt, I.; Kasai, E.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Khangulyan, D.; Khélifi, B.; Klepser, S.; Kluźniak, W.; Komin, Nu.; Konno, R.; Kosack, K.; Kostunin, D.; Kreter, M.; Lamanna, G.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J. -P.; Levy, C.; Lohse, T.; Lypova, I.; Mackey, J.; Majumdar, J.; Malyshev, D.; Malyshev, D.; Marandon, V.; Marchegiani, P.; Marcowith, A.; Mares, A.; Martí-Devesa, G.; Marx, R.; Maurin, G.; Meintjes, P. J.; Meyer, M.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Montanari, A.; Moore, C.; Morris, P.; Moulin, E.; Muller, J.; Murach, T.; Nakashima, K.; Nayerhoda, A.; de Naurois, M.; Ndiyavala, H.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Ohm, S.; Olivera-Nieto, L.; de Ona Wilhelmi, E.; Ostrowski, M.; Panter, M.; Panny, S.; Parsons, R. D.; Peron, G.; Peyaud, B.; Piel, Q.; Pita, S.; Poireau, V.; Noel, A. Priyana; Prokhorov, D. 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B.; Jin, W.; Kaaret, P.; Kertzman, M.; Kieda, D.; Kumar, S.; Lang, M. J.; Lundy, M.; Maier, G.; Moriarty, P.; Mukherjee, R.; Nieto, D.; Nievas-Rosillo, M.; O'Brien, S.; Ong, R. A.; Otte, A. N.; Patel, S.; Pfrang, K.; Pohl, M.; Prado, R. R.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Ribeiro, D.; Richards, G. T.; Roache, E.; Rulten, C.; Ryan, J. L.; Santander, M.; Sembroski, G. H.; Shang, R.; Weinstein, A.; Williams, D. A.; Williamson, T. J.; Eavn Collaboration; Hirota, Tomoya; Cui, Lang; Niinuma, Kotaro; Ro, Hyunwook; Sakai, Nobuyuki; Sawada-Satoh, Satoko; Wajima, Kiyoaki; Wang, Na; Liu, Xiang; Yonekura, Yoshinori, In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded., The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovacion (MICINN) (FPA2017-87859-P, FPA2017-85668-P, FPA2017- 82729-C6-5-R, FPA2017-90566-REDC, PID2019-104114RBC31, PID2019-104114RB-C32, PID2019-105510GB-C31,PID 2019-107847RB-C41, PID2019-107847RB-C42, PID2019- 107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant No. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and CEX2019- 000920-S, and “Maria de Maeztu” CEX2019-000918-M, the Unidad de Excelencia “Maria de Maeztu” MDM-2015-0509- 18-2 and the “la Caixa” Foundation (fellowship LCF/BQ/ PI18/11630012) and by the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; the Polish National Research Centre grant UMO-2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq, and FAPERJ. This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation and the Smithsonian Institution, by NSERC in Canada, and by the Helmholtz Association in Germany. This research used resources provided by the Open Science Grid, which is supported by the National Science Foundation and the U.S. Department of Energy’s Office of Science, and resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. We acknowledge the excellent work of the technical support staff at the Fred Lawrence Whipple Observatory and at the collaborating institutions in the construction and operation of the instrument.

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2021
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34. Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution

Author

Robert Freund, N. W. Halverson, Benjamin R. Ryan, Paul Shaw, André Young, Andreas Eckart, A. Montaña, Michael Titus, Chen Yu Yu, Gertie Geertsema, Gao Feng, Ronald Grosslein, Ranjani Srinivasan, David Ball, Pablo Torne, Roberto Garcia, Hiroki Okino, Kotaro Moriyama, Chris Eckert, Lupin C.C. Lin, Geoffrey B. Crew, Vernon Fath, Freek Roelofs, David Sánchez-Arguelles, Luciano Rezzolla, Makoto Inoue, Michael Bremer, Jongsoo Kim, James Hoge, Michael Janssen, David M. Gale, Mel Rose, Jason Dexter, Do-Young Byun, J. G. A. Wouterloot, Rubén Herrero-Illana, Daniel C. M. Palumbo, Ta Shun Wei, Ching Tang Liu, Bradford Benson, Jadyn Anczarski, Patrick M. Koch, Ken Young, Jae-Young Kim, Minfeng Gu, Mislav Baloković, Mariafelicia De Laurentis, Laurent Loinard, A. Jiménez-Rosales, Tomohisa Kawashima, Nicolas Pradel, Heino Falcke, Olivier Gentaz, Dirk Muders, Shami Chatterjee, Britton Jeter, Rocco Lico, Craig Walther, David J. James, Homin Jiang, Michael H. Hecht, Gopal Narayanan, Qingwen Wu, Pierre Martin-Cocher, Michael A. Nowak, Alexander W. Raymond, Gregory Desvignes, Anne Kathrin Baczko, Chet Ruszczyk, Yutaka Hasegawa, Chao-Te Li, M. C. H. Wright, Andrew Nadolski, Alan P. Marscher, Christopher Beaudoin, Harriet Parsons, Peñalver Juan, Karl M. Menten, Silke Britzen, Frédéric Gueth, Shu Hao Chang, Andrew Chael, Daryl Haggard, Rodrigo Córdova Rosado, Ru-Sen Lu, Mansour Karami, José L. Gómez, Sang-Sung Lee, Tirupati K. Sridharan, Karl Friedrich Schuster, Ronald Hesper, Richard L. Plambeck, Iain Coulson, Jason SooHoo, Aristeidis Noutsos, Svetlana G. Jorstad, Li Ming Lu, James M. Cordes, David H. Hughes, Jonathan Weintroub, Chih-Wei Locutus Huang, Katherine L. Bouman, Roger J. Cappallo, Lijing Shao, Christiaan D. Brinkerink, John Kuroda, Ramesh Karuppusamy, Iniyan Natarajan, Jessica Dempsey, George Nystrom, John E. Carlstrom, Sera Markoff, Mark Kettenis, Neal R. Erickson, Jason W. Henning, R. Laing, Huang Lei, Kevin A. Dudevoir, Ilje Cho, William Stahm, Juan-Carlos Algaba, Junhan Kim, Hotaka Shiokawa, Martin P. McColl, James M. Moran, Chi-kwan Chan, Timothy C. Chuter, Thomas W. Folkers, Yi Chen, Christopher Greer, Lia Medeiros, C. Y. Kuo, Kuo Chang Han, Shoko Koyama, William Snow, Rurik A. Primiani, Sjoerd T. Timmer, F. Peter Schloerb, Stephen R. McWhirter, Fumie Tazaki, Norbert Wex, Ming-Tang Chen, Nimesh A. Patel, Aaron Faber, Mark Derome, Kazunori Akiyama, W. B. Everett, Hiroshi Nagai, Andrei Lobanov, Ignacio Ruiz, Pierre Christian, N. Phillips, David C. Forbes, Don Sousa, Michael Lindqvist, Christopher Risacher, Wen Ping Lo, Geoffrey C. Bower, Bart Ripperda, Dominique Broguiere, Maciek Wielgus, Antony A. Stark, Raquel Fraga-Encinas, Hiroaki Nishioka, Philippe Raffin, Hugo Messias, Feryal Özel, Jun Yi Koay, Buell T. Jannuzi, Sandra Bustamente, Roberto Neri, Jinchi Hao, Ye-Fei Yuan, Garrett K. Keating, Lynn D. Matthews, Avery E. Broderick, Mark G. Rawlings, Ciriaco Goddi, Tod R. Lauer, Kamal Souccar, Alan L. Roy, S. Navarro, Luis C. Ho, Timothy Norton, Roger Brissenden, Doosoo Yoon, Jongho Park, Richard Lacasse, Paul T. P. Ho, Derek Ward-Thompson, Atish Kamble, Akihiko Hirota, S. Sánchez, D. A. Graham, Vincent Piétu, Kyle D. Massingill, M. Zeballos, Mahito Sasada, Hideo Ogawa, Ziri Younsi, Chih Cheng Chang, Alejandro F. Sáez-Madain, Christian M. Fromm, Ramesh Narayan, Shuichiro Tsuda, Ryan Berthold, Gibwa Musoke, Laura Vertatschitsch, Masanori Nakamura, Remo P. J. Tilanus, Cornelia Müller, Kimihiro Kimura, Roman Gold, Venkatessh Ramakrishnan, Yuzhu Cui, Frederick K. Baganoff, Alan R. Whitney, Aleksandar Popstefanija, Helge Rottmann, Yuan Feng, Ralph Eatough, Tuomas Savolainen, Neil M. Nagar, Alexander Allardi, M. Mora-Klein, Thomas Bronzwaer, Mark Gurwell, Bong Won Sohn, Ivan Marti-Vidal, Chih Chiang Han, Hung Yi Pu, Yan-Rong Li, Shan Shan Zhao, Song Chu Chang, Zhi-Qiang Shen, John F. C. Wardle, Carsten Kramer, Koushik Chatterjee, Wagner Jan, Tomoaki Oyama, Ray Blundell, Motoki Kino, Alan E. E. Rogers, Rebecca Azulay, Jordy Davelaar, Tyler Trent, Satoki Matsushita, Kazi L.J. Rygl, Shuo Zhang, John E. Barrett, Peter Oshiro, Ryan Chilson, Jorge A. Preciado-López, Daniel Michalik, Peter Galison, Uwe Bach, Ilse van Bemmel, Pim Schellart, Michael D. Johnson, Jiang Wu, J. Anton Zensus, S. A. Dzib, Arturo I. Gómez-Ruiz, Meyer Zhao Zheng, David John, Dimitrios Psaltis, Daniel P. Marrone, M. Poirier, Shiro Ikeda, Ralph G. Marson, A. Hernandez-Gomez, Sven Dornbusch, George Reiland, Mareki Honma, J. Blanchard, Ed Fomalont, Taehyun Jung, Izumi Mizuno, Monika Moscibrodzka, Vincent L. Fish, Matthew R. Dexter, Paul Tiede, Rodrigo Amestica, Nicholas R. MacDonald, Gisela N. Ortiz-León, Colin J. Lonsdale, Callie Matulonis, Charles F. Gammie, Per Friberg, Boris Georgiev, W. Boland, Ramprasad Rao, Guang-Yao Zhao, Joseph R. Farah, Zhiyuan Li, Hector Olivares, Sara Issaoun, Elisabetta Liuzzo, C. M. Violette Impellizzeri, Michael Kramer, Oliver Porth, Thomas P. Krichbaum, Dominic W. Pesce, Daniel R. van Rossum, David R. Smith, Robert Wharton, Kuan Yu Liu, David P. Woody, Arash Roshanineshat, Sheperd S. Doeleman, Chung Chen Chen, Ziyan Zhu, Ue-Li Pen, Yosuke Mizuno, Prather Ben, Sascha Trippe, Walter Alef, Liu Kuo, Alexandra S. Rahlin, William Montgomerie, George N. Wong, Jirong Mao, Kazuhiro Hada, Efthalia Traianou, John Conway, Remi Sassella, Eduardo Ros, Kevin M. Silva, Derek Kubo, E. Castillo-Domínguez, Huib Jan van Langevelde, Keiichi Asada, Des Small, Joseph Neilsen, Chi H. Nguyen, Chunchong Ni, Yusuke Kono, Ryan Keisler, Paul Yamaguchi, Lindy Blackburn, Erik M. Leitch, Roger Deane, Lucy M. Ziurys, K. T. Story, Joseph Crowley, Nathan Whitehorn, Stefan Heyminck, Kenji Toma, Antxon Alberdi, Yau De Huang, Dan Bintley, Y Kim, J., Krichbaum, T. P., Broderick, A. E., Wielgus, M., Blackburn, L., Gomez, J. -L., Johnson, M. D., Bouman, K. L., Chael, A., Akiyama, K., Jorstad, S., Marscher, A. P., Issaoun, S., Janssen, M., Chan, C. -K., Savolainen, T., Pesce, D. W., Ozel, F., De Laurentis, M., Deane, R., Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Ministerio de Economía y Competitividad (España), European Commission, National Aeronautics and Space Administration (US), Max Planck Institute for Radio Astronomy, Perimeter Institute for Theoretical Physics, Harvard University, CSIC, Princeton University, Boston University, Radboud University Nijmegen, University of Arizona, Anne Lähteenmäki Group, Academia Sinica - Institute of Astronomy and Astrophysics, Massachusetts Institute of Technology, East Asian Observatory, Nederlandse Onderzoekschool voor Astronomie, Academia Sinica, Institut de Radio Astronomie Millimétrique, Korea Astronomy and Space Science Institute, University of Chicago, Cornell University, University of Amsterdam, CAS - Shanghai Astronomical Observatory, Chalmers University of Technology, National Astronomical Observatory of Japan, University of Naples Federico II, University of Pretoria, University of Colorado Boulder, National Radio Astronomy Observatory, Goethe University Frankfurt, University of Illinois at Urbana-Champaign, University of Waterloo, Instituto Nacional de Astrofisica Optica y Electronica, University of Groningen, Peking University, Max Planck Institute for Extraterrestrial Physics, Joint Institute for VLBI in Europe, California Institute of Technology, National Sun Yat-sen University, National Optical Astronomy Observatory, CAS - Institute of High Energy Physics, Nanjing University, INAF Istituto di Radioastronomia, Instituto de Radioastronomía y Astrofísica, CAS - National Astronomical Observatories, Universidad de Valencia, Universidad de Concepción, University of Massachusetts, Rhodes University, University of California Berkeley, Los Alamos National Laboratory, IRAM, Tohoku University, Seoul National University, Brandeis University, University of Central Lancashire, Huazhong University of Science and Technology, University of Science and Technology of China, University of Vermont, Villanova University, United States Department of Energy, Western University, Royal Netherlands Meteorological Institute, McGill University, Osaka Prefecture University, European Southern Observatory Santiago, University of Manchester, National Radio Astronomy Observatory Socorro, Rochester Institute of Technology, Washington University St. Louis, Systems and Technology Research, Georgia Institute of Technology, Stanford University, University of California Los Angeles, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Gravitation and Astroparticle Physics Amsterdam

Subjects
ACTIVE GALACTIC NUCLEI, Brightness, Active galactic nucleus, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astronomy, galaxies: active, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Submillimeter Array, FLOWS, SCALE CIRCULAR-POLARIZATION, 0103 physical sciences, Very-long-baseline interferometry, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Event Horizon Telescope, [PHYS]Physics [physics], Jet (fluid), 010308 nuclear & particles physics, Astronomy and Astrophysics, FLARE, galaxies: jets, individual: 3C 279 [Galaxies], LONG, VARIABILITY, galaxies: individual: 3C 279, GAMMA-RAY, QUASARS, 13. Climate action, Space and Planetary Science, techniques: interferometric, Brightness temperature, ACCRETION DISKS, interferometric [Techniques], jets [Galaxies], RELATIVISTIC JETS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society.--All authors: Kim, Jae-Young; Krichbaum, Thomas P.; Broderick, Avery E.; Wielgus, Maciek; Blackburn, Lindy; Gómez, José L.; Johnson, Michael D.; Bouman, Katherine L.; Chael, Andrew; Akiyama, Kazunori; Jorstad, Svetlana; Marscher, Alan P.; Issaoun, Sara; Janssen, Michael; Chan, Chi-kwan; Savolainen, Tuomas; Pesce, Dominic W.; Özel, Feryal; Alberdi, Antxon; Alef, Walter Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bintley, Dan; Boland, Wilfred; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Markoff, Sera; Marrone, Daniel P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Musoke, Gibwa; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Ward-Thompson, Derek; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Algaba, Juan-Carlos; Allardi, Alexander; Amestica, Rodrigo; Anczarski, Jadyn; Bach, Uwe; Baganoff, Frederick K.; Beaudoin, Christopher; Benson, Bradford A.; Berthold, Ryan; Blanchard, Jay M.; Blundell, Ray; Bustamente, Sandra; Cappallo, Roger; Castillo-Domínguez, Edgar; Chang, Chih-Cheng; Chang, Shu-Hao; Chang, Song-Chu; Chen, Chung-Chen; Chilson, Ryan; Chuter, Tim C.; Rosado, Rodrigo Córdova; Coulson, Iain M.; Crowley, Joseph; Derome, Mark; Dexter, Matthew; Dornbusch, Sven; Dudevoir, Kevin A.; Dzib, Sergio A.; Eckart, Andreas; Eckert, Chris; Erickson, Neal R.; Everett, Wendeline B.; Faber, Aaron; Farah, Joseph R.; Fath, Vernon; Folkers, Thomas W.; Forbes, David C.; Freund, Robert; Gale, David M.; Gao, Feng; Geertsema, Gertie; Graham, David A.; Greer, Christopher H.; Grosslein, Ronald; Gueth, Frédéric; Haggard, Daryl; Halverson, Nils W.; Han, Chih-Chiang; Han, Kuo-Chang; Hao, Jinchi; Hasegawa, Yutaka; Henning, Jason W.; Hernández-Gómez, Antonio; Herrero-Illana, Rubén; Heyminck, Stefan; Hirota, Akihiko; Hoge, James; Huang, Yau-De; Violette Impellizzeri, C. M.; Jiang, Homin; John, David; Kamble, Atish; Keisler, Ryan; Kimura, Kimihiro; Kono, Yusuke; Kubo, Derek; Kuroda, John; Lacasse, Richard; Laing, Robert A.; Leitch, Erik M.; Li, Chao-Te; Lin, Lupin C. -C.; Liu, Ching-Tang; Liu, Kuan-Yu; Lu, Li-Ming; Marson, Ralph G.; Martin-Cocher, Pierre L.; Massingill, Kyle D.; Matulonis, Callie; McColl, Martin P.; McWhirter, Stephen R.; Messias, Hugo; Meyer-Zhao, Zheng; Michalik, Daniel; Montaña, Alfredo; Montgomerie, William; Mora-Klein, Matias; Muders, Dirk; Nadolski, Andrew; Navarro, Santiago; Neilsen, Joseph; Nguyen, Chi H.; Nishioka, Hiroaki; Norton, Timothy; Nowak, Michael A.; Nystrom, George; Ogawa, Hideo; Oshiro, Peter; Oyama, Tomoaki; Parsons, Harriet; Peñalver, Juan; Phillips, Neil M.; Poirier, Michael; Pradel, Nicolas; Primiani, Rurik A.; Raffin, Philippe A.; Rahlin, Alexandra S.; Reiland, George; Risacher, Christopher; Ruiz, Ignacio; Sáez-Madaín, Alejandro F.; Sassella, Remi; Schellart, Pim; Shaw, Paul; Silva, Kevin M.; Shiokawa, Hotaka; Smith, David R.; Snow, William; Souccar, Kamal; Sousa, Don; Sridharan, Tirupati K.; Srinivasan, Ranjani; Stahm, William; Stark, Antony A.; Story, Kyle; Timmer, Sjoerd T.; Vertatschitsch, Laura; Walther, Craig; Wei, Ta-Shun; Whitehorn, Nathan; Whitney, Alan R.; Woody, David P.; Wouterloot, Jan G. A.; Wright, Melvin; Yamaguchi, Paul; Yu, Chen-Yu; Zeballos, Milagros; Zhang, Shuo; Ziurys, Lucy; Event Horizon Telescope Collaboration, 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths. © J.-Y. Kim et al. 2020., The authors of the present paper thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt projects 1171506 and 3190878, BASAL AFB-170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico -Universidad Nacional Autonoma de Mexico (DGAPA -UNAM, project IN112417); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-inAid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJSSW-SLH057, QYZDJ-SSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Malaysian Fundamental Research Grant Scheme (FRGS, grant FRGS/1/2019/STG02/UM/02/6); the Max-PlanckGesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649 and Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. r , for NASA, under contract NAS5-26555); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1312651, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants PGC2018-098915-B-C21, AYA201680889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X; the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI1743442. XSEDE Stampede2 resource at TACC was allocated through TGAST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario. r ca), Calcul Quebec (http://www.calculquebec.ca) and Compute Canada (http://www.computecanada.ca).We thank the sta ff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V, ADS/JAO.ALMA#2016.1.01176.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrofisica, Optica, y Electronica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geografico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the National Science Foundation through grant PLR1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended sta ff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. r This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), which consists of telescopes operated by the MPIfR, IRAM, Onsala, Metsahovi, Yebes, the Korean VLBI Network, the Green Bank Observatory and the Very Long Baseline Array (VLBA). The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. The data were correlated at the correlator of the MPIfR in Bonn, Germany. This study makes use of 43 GHz VLBA data from the VLBA-BU Blazar Monitoring Program (VLBABU-BLAZAR; http://www.bu.edu/blazars/VLBAproject.html), funded by NASA through the Fermi Guest Investigator Program.

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2020
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35. THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope

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Jessica Dempsey, Masanori Nakamura, Elisabetta Liuzzo, Michael Kramer, Oliver Porth, Michael Bremer, Walter Alef, Iniyan Natarajan, Thomas P. Krichbaum, Aleksandar Popstefanija, Helge Rottmann, Koushik Chatterjee, F. Peter Schloerb, Rebecca Azulay, Lynn D. Matthews, Avery E. Broderick, Dominic W. Pesce, Charles F. Gammie, Karl Friedrich Schuster, Ronald Hesper, Daniel R. van Rossum, Thomas Bronzwaer, Minfeng Gu, Satoki Matsushita, Ramesh Karuppusamy, Kazi L.J. Rygl, Katherine L. Bouman, R. P. Eatough, Norbert Wex, Jonathan Weintroub, Chet Ruszczyk, Ilje Cho, Andrei P. Lobanov, Dan Bintley, Yan-Rong Li, Alan E. E. Rogers, Sara Issaoun, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, Jorge A. Preciado-López, Michael Lindqvist, Kazunori Akiyama, Makoto Inoue, George N. Wong, Wen Ping Lo, Geoffrey C. Bower, Shan Shan Zhao, Maciek Wielgus, James M. Moran, Laurent Loinard, Bart Ripperda, S. Sánchez, Hector Olivares, Raquel Fraga-Encinas, Mark G. Rawlings, Mark Gurwell, Ivan Marti-Vidal, Dominique Broguiere, Zhiqiang Shen, Mariafelicia De Laurentis, John E. Carlstrom, Carsten Kramer, Kuo Liu, A. Jiménez-Rosales, Per Friberg, Yi Chen, Kazuhiro Hada, Huib Jan van Langevelde, Ciriaco Goddi, Feng Yuan, Izumi Mizuno, Jan Wagner, Vincent L. Fish, Hung Yi Pu, Tomoaki Oyama, Sheperd S. Doeleman, Ed Fomalont, Boris Georgiev, Jordy Davelaar, Hiroshi Nagai, Doosoo Yoon, Motoki Kino, Remo P. J. Tilanus, Michael Janssen, Michael Titus, Paul Tiede, Jirong Mao, Colin J. Lonsdale, Mel Rose, Freek Roelofs, W. Boland, Ramprasad Rao, Mansour Karami, José L. Gómez, John E. Barrett, Heino Falcke, Guang-Yao Zhao, Peter Galison, Ilse van Bemmel, C. Y. Kuo, Mislav Baloković, Shami Chatterjee, Robert Wharton, Keiichi Asada, James M. Cordes, Ken H. Young, Michael D. Johnson, Mareki Honma, Monika Moscibrodzka, Olivier Gentaz, Ziyan Zhu, Wu Jiang, Des Small, Jason SooHoo, Svetlana G. Jorstad, Paul T. P. Ho, Silke Britzen, J. Anton Zensus, Zhiyuan Li, Ue-Li Pen, Yosuke Mizuno, David J. James, Vincent Piétu, Tomohisa Kawashima, Ming-Tang Chen, Roberto Garcia, Nicholas R. MacDonald, Roman Gold, Gisela N. Ortiz-León, Sascha Trippe, Gopal Narayanan, Alexander W. Raymond, Gregory Desvignes, Venkatessh Ramakrishnan, Anne Kathrin Baczko, Geoffrey B. Crew, Alan P. Marscher, Bong Won Sohn, Fumie Tazaki, André Young, Ru-Sen Lu, Benjamin R. Ryan, Roberto Neri, Pablo Torne, David Sánchez-Arguelles, John Wardle, Qingwen Wu, Michael H. Hecht, Chunchong Ni, Christian M. Fromm, Lei Huang, Cornelia Müller, Efthalia Traianou, Luis C. Ho, John Conway, Eduardo Ros, Sang-Sung Lee, Andrew Chael, Jongho Park, Ye-Fei Yuan, Hiroki Okino, Richard L. Plambeck, Ziri Younsi, Tuomas Savolainen, Neil M. Nagar, Luciano Rezzolla, Jongsoo Kim, Daniel C. M. Palumbo, Lindy Blackburn, Yuzhu Cui, Ben Prather, Shoko Koyama, Roger Deane, Patrick M. Koch, Britton Jeter, Rocco Lico, Kenji Toma, Do-Young Byun, Antxon Alberdi, Jun Yi Koay, Shuichiro Tsuda, Jae-Young Kim, David H. Hughes, Karl M. Menten, Aristeidis Noutsos, Taehyun Jung, Mark Kettenis, Kotaro Moriyama, Roger Brissenden, Mahito Sasada, Ramesh Narayan, Garrett K. Keating, Perimeter Institute for Theoretical Physics, National Radio Astronomy Observatory Socorro, CSIC, Max Planck Institute for Radio Astronomy, Academia Sinica - Institute of Astronomy and Astrophysics, Harvard University, Massachusetts Institute of Technology, East Asian Observatory, Nederlandse Onderzoekschool voor Astronomie, Academia Sinica, Institut de Radio Astronomie Millimétrique, Radboud University Nijmegen, Korea Astronomy and Space Science Institute, University of Chicago, Cornell University, University of Amsterdam, CAS - Shanghai Astronomical Observatory, Chalmers University of Technology, National Astronomical Observatory of Japan, Goethe University Frankfurt, University of Pretoria, University of Illinois at Urbana-Champaign, University of Groningen, Peking University, Instituto Nacional de Astrofisica Optica y Electronica, Max Planck Institute for Extraterrestrial Physics, St. Petersburg State University, Joint Institute for VLBI in Europe, National Sun Yat-sen University, CAS - Institute of High Energy Physics, Nanjing University, National Institute for Astrophysics, Universidad Nacional Autónoma de México, Chinese Academy of Sciences, Boston University, University of Valencia, Universidad de Concepción, University of Massachusetts, Rhodes University, University of California Berkeley, University of Arizona, Los Alamos National Laboratory, Instituto de Radioastronomía Milimétrica, Anne Lähteenmäki Group, Tohoku University, Seoul National University, Brandeis University, Huazhong University of Science and Technology, University of Science and Technology of China, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, High Energy Astrophys. & Astropart. Phys (API, FNWI), European Research Council, Academy of Finland, European Commission, Gordon and Betty Moore Foundation, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), Ministry of Education, Culture, Sports, Science and Technology (Japan), Japan Society for the Promotion of Science, National Key Research and Development Program (China), Leverhulme Trust, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), Natural Sciences and Engineering Research Council of Canada, National Science Foundation (US), National Research Foundation of Korea, Netherlands Organization for Scientific Research, Swedish Research Council, Ministry of Research, Technology and Higher Education of the Republic of Indonesia, Russian Science Foundation, Ministerio de Economía y Competitividad (España), Department of Energy (US), Ministero dell'Economia e delle Finanze, National Natural Science Foundation of China, Ministero dell'Istruzione, dell'Università e della Ricerca, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Astronomy, Broderick, A. E., Gold, R., Karami, M., Preciado-Lopez, J. A., Tiede, P., Pu, H. -Y., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gomez, J. L., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Inoue, M., Issaoun, S., James, D. J., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Johnson, M. D., Jorstad, S., Jung, T., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Palumbo, D. C. M., Park, J., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Rottmann, H., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Traianou, E., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., and Zhu, Z.

Subjects
010504 meteorology & atmospheric sciences, Exploit, Astronomy, 01 natural sciences, Data type, Set (abstract data type), Galactic center, 0103 physical sciences, Very-long-baseline interferometry, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Very long baseline interferometry, Physics, Event Horizon Telescope, Supermassive black hole, Astrophysical black holes, Galactic Center, Astronomy and Astrophysics, Black hole, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astronomy data analysis, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Algorithm, Submillimeter astronomy
Abstract

This is an open access article.-- Full list of authors: Broderick, Avery E.; Gold, Roman; Karami, Mansour; Preciado-López, Jorge A.; Tiede, Paul; Pu, Hung-Yi; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; Issaoun, Sara; James, David J.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Jung, Taehyun; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Krichbaum, Thomas P.; Kuo, Cheng-Yu; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Rottmann, Helge; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wielgus, Maciek; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Event Horizon Telescope Collaboration., The Event Horizon Telescope (EHT) provides the unprecedented ability to directly resolve the structure and dynamics of black hole emission regions on scales smaller than their horizons. This has the potential to critically probe the mechanisms by which black holes accrete and launch outflows, and the structure of supermassive black hole spacetimes. However, accessing this information is a formidable analysis challenge for two reasons. First, the EHT natively produces a variety of data types that encode information about the image structure in nontrivial ways; these are subject to a variety of systematic effects associated with very long baseline interferometry and are supplemented by a wide variety of auxiliary data on the primary EHT targets from decades of other observations. Second, models of the emission regions and their interaction with the black hole are complex, highly uncertain, and computationally expensive to construct. As a result, the scientific utilization of EHT observations requires a flexible, extensible, and powerful analysis framework. We present such a framework, Themis, which defines a set of interfaces between models, data, and sampling algorithms that facilitates future development. We describe the design and currently existing components of Themis, how Themis has been validated thus far, and present additional analyses made possible by Themis that illustrate its capabilities. Importantly, we demonstrate that Themis is able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities. Themis has already been used extensively in the scientific analysis and interpretation of the first EHT observations of M87. © 2020. The Author(s). Published by the American Astronomical Society., This work was made possible by the facilities of the Shared Hierarchical Academic Research Computing Network (SHARCNET: www.sharcnet.ca) and Compute/Calcul Canada (www.computecanada.ca). Computations were made on the supercomputer Mammouth Parallele 2 from University of Sherbrooke, managed by Calcul Quebec and Compute Canada. The operation of this supercomputer is funded by the Canada Foundation for Innovation (CFI), the ministere de l'Economie, de la science et de l'innovation du Quebec (MESI), and the Fonds de recherche du Quebec-Nature et technologies (FRQ-NT). This work was supported in part by Perimeter Institute for Theoretical Physics. Research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade. A.E.B. thanks the Delaney Family for their generous financial support via the Delaney Family John A. Wheeler Chair at Perimeter Institute. A.E.B., P.T., and M.K. receive additional financial support from the Natural Sciences and Engineering Research Council of Canada through a Discovery Grant. R.G. receives additional support from the ERC synergy grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant No. 610058). We thank Jason Dexter for helpful comments and suggestions. We further thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; Black Hole Initiative at Harvard University, through grants from the John Templeton Foundation and the Gordon and Betty Moore Foundation; the China Scholarship Council; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB-170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico-Universidad Nacional Autonoma de Mexico (DGAPA-UNAM, project IN112417); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043. 513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants PGC2018-098915-B-C21, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation program under grant agreement No. 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart.

Published
2020
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36. SYMBA: An end-to-end VLBI synthetic data generation pipeline. Simulating Event Horizon Telescope observations of M 87

Author

F. Roelofs, M. Janssen, I. Natarajan, R. Deane, J. Davelaar, H. Olivares, O. Porth, S. N. Paine, K. L. Bouman, R. P. J. Tilanus, I. M. van Bemmel, H. Falcke, K. Akiyama, A. Alberdi, W. Alef, K. Asada, R. Azulay, A. Baczko, D. Ball, M. Baloković, J. Barrett, D. Bintley, L. Blackburn, W. Boland, G. C. Bower, M. Bremer, C. D. Brinkerink, R. Brissenden, S. Britzen, A. E. Broderick, D. Broguiere, T. Bronzwaer, D. Byun, J. E. Carlstrom, A. Chael, C. Chan, S. Chatterjee, K. Chatterjee, M. Chen, Y. Chen, I. Cho, P. Christian, J. E. Conway, J. M. Cordes, G. B. Crew, Y. Cui, M. De Laurentis, J. Dempsey, G. Desvignes, J. Dexter, S. S. Doeleman, R. P. Eatough, V. L. Fish, E. Fomalont, R. Fraga-Encinas, P. Friberg, C. M. Fromm, J. L. Gómez, P. Galison, C. F. Gammie, R. García, O. Gentaz, B. Georgiev, C. Goddi, R. Gold, M. Gu, M. Gurwell, K. Hada, M. H. Hecht, R. Hesper, L. C. Ho, P. Ho, M. Honma, C. L. Huang, L. Huang, D. H. Hughes, S. Ikeda, M. Inoue, S. Issaoun, D. J. James, B. T. Jannuzi, B. Jeter, W. Jiang, M. D. Johnson, S. Jorstad, T. Jung, M. Karami, R. Karuppusamy, T. Kawashima, G. K. Keating, M. Kettenis, J. Kim, M. Kino, J. Y. Koay, P. M. Koch, S. Koyama, M. Kramer, C. Kramer, T. P. Krichbaum, C. Kuo, T. R. Lauer, S. Lee, Y. Li, Z. Li, M. Lindqvist, R. Lico, K. Liu, E. Liuzzo, W. Lo, A. P. Lobanov, L. Loinard, C. Lonsdale, R. Lu, N. R. MacDonald, J. Mao, S. Markoff, D. P. Marrone, A. P. Marscher, I. Martí-Vidal, S. Matsushita, L. D. Matthews, L. Medeiros, K. M. Menten, Y. Mizuno, I. Mizuno, J. M. Moran, K. Moriyama, M. Moscibrodzka, C. Müller, H. Nagai, N. M. Nagar, M. Nakamura, R. Narayan, G. Narayanan, R. Neri, C. Ni, A. Noutsos, H. Okino, G. N. Ortiz-León, T. Oyama, F. Özel, D. C. M. Palumbo, N. Patel, U. Pen, D. W. Pesce, V. Piétu, R. Plambeck, A. PopStefanija, B. Prather, J. A. Preciado-López, D. Psaltis, H. Pu, V. Ramakrishnan, R. Rao, M. G. Rawlings, A. W. Raymond, L. Rezzolla, B. Ripperda, A. Rogers, E. Ros, M. Rose, A. Roshanineshat, H. Rottmann, A. L. Roy, C. Ruszczyk, B. R. Ryan, K. L. J. Rygl, S. Sánchez, D. Sánchez-Arguelles, M. Sasada, T. Savolainen, F. P. Schloerb, K. Schuster, L. Shao, Z. Shen, D. Small, B. Won Sohn, J. SooHoo, F. Tazaki, P. Tiede, M. Titus, K. Toma, P. Torne, E. Traianou, T. Trent, S. Trippe, S. Tsuda, H. J. van Langevelde, D. R. van Rossum, J. Wagner, J. Wardle, J. Weintroub, N. Wex, R. Wharton, M. Wielgus, G. N. Wong, Q. Wu, A. Young, K. Young, Z. Younsi, F. Yuan, Y. Yuan, J. A. Zensus, G. Zhao, S. Zhao, Z. Zhu, High Energy Astrophys. & Astropart. Phys (API, FNWI), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Roelofs, F., Janssen, M., Natarajan, I., Deane, R., Davelaar, J., Olivares, H., Porth, O., Paine, S. N., Bouman, K. L., Tilanus, R. P. J., Van Bemmel, I. M., Falcke, H., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D., Carlstrom, J. E., Chael, A., Chan, C., Chatterjee, S., Chatterjee, K., Chen, M., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., De Laurentis, M., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C., Lauer, T. R., Lee, S., Li, Y., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Neri, R., Ni, C., Noutsos, A., Okino, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K., Shao, L., Shen, Z., Small, D., Won Sohn, B., Soohoo, J., Tazaki, F., Tiede, P., Titus, M., Toma, K., Torne, P., Traianou, E., Trent, T., Trippe, S., Tsuda, S., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y., Zensus, J. A., Zhao, G., Zhao, S., Zhu, Z., Universidad de Concepción, Anne Lähteenmäki Group, Radboud University, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, and Astronomy

Subjects
010504 meteorology & atmospheric sciences, Computer science, Image quality, Pipeline (computing), Astronomy, black hole physics, 01 natural sciences, Black hole physic, 0103 physical sciences, Very-long-baseline interferometry, Calibration, Angular resolution, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Event Horizon Telescope, astro-ph.HE, Atmospheric effect, Astrophysics::Instrumentation and Methods for Astrophysics, techniques: high angular resolution, Astronomy and Astrophysics, telescopes, Black hole physics, Atmospheric effects, Galaxies, Techniques, high angular resolution [Techniques], 13. Climate action, Space and Planetary Science, techniques: interferometric, nuclei [Galaxies], interferometric, nuclei, interferometric [Techniques], galaxies: nuclei, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], high angular resolution, Telescopes, atmospheric effects, astro-ph.IM
Abstract

Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images. © 2020 ESO., This work is supported by the ERC Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (Grant 610058). I. Natarajan and R. Deane are grateful for the support from the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa. The authors of the present paper further thank the following organizations and programmes: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comision Nacional de Investigacio Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB-170002, ALMAconicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico-Universidad Nacional Autonoma de Mexico (DGAPA-UNAM, project IN112417); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the GenT Program (Generalitat Valenciana) under project CIDEGENT/2018/021; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); NASA through the NASA Hubble Fellowship grant #HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. , for NASA, under contract NAS5-26555; the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1312651, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Princeton/Flatiron Postdoctoral Prize Fellowship; the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants AYA2015-63939-C21-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI1743442. XSEDE Stampede2 resource at TACC was allocated through TGAST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www. calculquebec.ca) and Compute Canada (http://www.computecanada.ca).We thank the sta ff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2017.1.00841.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrofisica, Optica, y Electronica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geografico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the National Science Foundation through grant PLR-1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. The software presented in this work makes use of the Numpy (van derWalt et al. 2011), Scipy (Jones et al. 2001), Astropy (Astropy Collaboration 2013, 2018) libraries and the KERN software bundle (Molenaar & Smirnov 2018).

Published
2020
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37. Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope

Author

Thomas Bronzwaer, Tyler Trent, James M. Cordes, Jonathan Weintroub, Roger Deane, Roberto Neri, Satoki Matsushita, John E. Barrett, Mariafelicia De Laurentis, Kuo Liu, A. Jiménez-Rosales, Mansour Karami, José L. Gómez, Shan Shan Zhao, Kazi L.J. Rygl, Minfeng Gu, Michael Kramer, Luis C. Ho, Katherine L. Bouman, Mislav Baloković, Shami Chatterjee, Peter Galison, Ziyan Zhu, Ben Prather, Makoto Inoue, Enrico Barausse, Chunchong Ni, Oliver Porth, André Young, Monika Moscibrodzka, Arturo I. Gómez-Ruiz, Shoko Koyama, Pierre Christian, Kazunori Akiyama, Alan L. Roy, S. Sánchez, Jorge A. Preciado-López, Efthalia Traianou, Maciek Wielgus, Koushik Chatterjee, Jae-Young Kim, Michael Janssen, Jessica Dempsey, Yi Chen, Dimitrios Psaltis, Daniel P. Marrone, Ue-Li Pen, Yosuke Mizuno, David MacMahon, Raquel Fraga-Encinas, Mark G. Rawlings, F. Peter Schloerb, Michael Bremer, Ken H. Young, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, John Conway, Sara Issaoun, Alan E. E. Rogers, Rebecca Azulay, Eduardo Ros, Ilse van Bemmel, Nicholas R. MacDonald, Mareki Honma, Sera Markoff, Laurent Loinard, Thomas P. Krichbaum, David H. Hughes, Tuomas Savolainen, Neil M. Nagar, Elisabetta Liuzzo, Mark Gurwell, Gisela N. Ortiz-León, Michael D. Johnson, Chet Ruszczyk, Pablo Torne, Ivan Marti-Vidal, Nicola Marchili, Silke Britzen, Huib Jan van Langevelde, Bong Won Sohn, Colin J. Lonsdale, Sascha Trippe, J. Anton Zensus, David Ball, Norbert Wex, Nimesh A. Patel, Walter Alef, Christian M. Fromm, Cornelia Müller, Lindy Blackburn, Roberto Garcia, S. A. Dzib, Michael Lindqvist, Hung Yi Pu, John F. C. Wardle, Tomoaki Oyama, Feng Yuan, Junhan Kim, Remo P. J. Tilanus, Dominic W. Pesce, Keiichi Asada, Kenji Toma, Antxon Alberdi, Heino Falcke, Carsten Kramer, Izumi Mizuno, Jan Wagner, Ciriaco Goddi, Patrick M. Koch, Motoki Kino, Geoffrey B. Crew, Britton Jeter, Vincent L. Fish, Rocco Lico, Des Small, Karl M. Menten, Aristeidis Noutsos, Buell T. Jannuzi, Yan-Rong Li, David Sánchez-Arguelles, Wu Jiang, Tod R. Lauer, Matthew R. Dexter, Luciano Rezzolla, Zhiyuan Li, Vincent Piétu, Masanori Nakamura, Jordy Davelaar, Roman Gold, Antonios Nathanail, Olivier Gentaz, Ed Fomalont, Dan Bintley, Paul Tiede, George N. Wong, Jirong Mao, Jongsoo Kim, Karl Friedrich Schuster, Ronald Hesper, Feryal Özel, Venkatessh Ramakrishnan, Taehyun Jung, Mark Kettenis, David J. James, Iniyan Natarajan, Ramesh Karuppusamy, Daniel C. M. Palumbo, Paul T. P. Ho, Derek Ward-Thompson, Kazuhiro Hada, Daniel R. van Rossum, Gopal Narayanan, Alan P. Marscher, Kotaro Moriyama, Ilje Cho, Roger Brissenden, Per Friberg, Alexander W. Raymond, Sheperd S. Doeleman, Chi-kwan Chan, John E. Carlstrom, Anne Kathrin Baczko, Zhi-Qiang Shen, Boris Georgiev, Qingwen Wu, Jason Dexter, Do-Young Byun, Charles F. Gammie, W. Boland, Ru-Sen Lu, Aleksandar Popstefanija, Ramprasad Rao, Helge Rottmann, Mahito Sasada, Guang-Yao Zhao, Sang-Sung Lee, G. Desvignes, Lynn D. Matthews, Avery E. Broderick, Lia Medeiros, Jun Yi Koay, Michael Titus, Ramesh Narayan, Ralph Eatough, Ziri Younsi, C. Y. Kuo, Shuichiro Tsuda, Jongho Park, Gibwa Musoke, Freek Roelofs, Ming-Tang Chen, Hiroshi Nagai, Andrei Lobanov, Yuzhu Cui, Michael H. Hecht, Lei Huang, Hector Olivares, Ye-Fei Yuan, Garrett K. Keating, Andrew Chael, Jason SooHoo, Robert Wharton, Arash Roshanineshat, Fumie Tazaki, Svetlana G. Jorstad, Melvyn Wright, Wen Ping Lo, Geoffrey C. Bower, Bart Ripperda, Dominique Broguiere, Doosoo Yoon, Richard L. Plambeck, James M. Moran, Benjamin R. Ryan, Hiroki Okino, Mel Rose, Tomohisa Kawashima, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Wielgus, M., Akiyama, K., Blackburn, L., Chan, C. -K., Dexter, J., Doeleman, S. S., Fish, V. L., Issaoun, S., Johnson, M. D., Krichbaum, T. P., Lu, R. -S., Pesce, D. W., Wong, G. N., Bower, G. C., Broderick, A. E., Chael, A., Chatterjee, K., Gammie, C. F., Georgiev, B., Hada, K., Loinard, L., Markoff, S., Marrone, D. P., Plambeck, R., Weintroub, J., Dexter, M., Macmahon, D. H. E., Wright, M., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barausse, E., Barrett, J., Bintley, D., Boland, W., Bouman, K. L., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chatterjee, S., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dzib, S. A., Eatough, R. P., Falcke, H., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Galison, P., Garcia, R., Gentaz, O., Goddi, C., Gold, R., Gomez, J. L., Gomez-Ruiz, A. I., Gu, M., Gurwell, M., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Inoue, M., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Jimenez-Rosales, A., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Lico, R., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Lonsdale, C., Macdonald, N. R., Mao, J., Marchili, N., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Musoke, G., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Nathanail, A., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., I¿½zel, F., Palumbo, D. C. M., Park, J., Patel, N., Pen, U. -L., Pietu, V., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Traianou, E., Trippe, S., Tsuda, S., Bemmel, I. V., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Ward-Thompson, D., Wex, N., Wharton, R., Wu, Q., Yoon, D., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, European Research Council, European Commission, National Aeronautics and Space Administration (US), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Astronomy, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
Brightness, Active galactic nucleus, 010504 meteorology & atmospheric sciences, Event horizon, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Galaxy accretion disks, FOS: Physical sciences, Astrophysics, F500, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Settore FIS/05 - Astronomia e Astrofisica, Supermassive black holes, 0103 physical sciences, Very-long-baseline interferometry, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Computer Vision and Robotics (Autonomous Systems), Astronomy data modeling, Very long baseline interferometry, 0105 earth and related environmental sciences, Black holes, Galaxy accretion, Active galactic nuclei, Low-luminosity active galactic nuclei, Radio interferometry, Event Horizon Telescope, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Supermassive black hole, Astronomy and Astrophysics, Position angle, Galaxy, Medical Image Processing, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

All authors: Wielgus, Maciek; Akiyama, Kazunori; Blackburn, Lindy; Chan, Chi-kwan; Dexter, Jason; Doeleman, Sheperd S.; Fish, Vincent L.; Issaoun, Sara; Johnson, Michael D.; Krichbaum, Thomas P.; Lu, Ru-Sen; Pesce, Dominic W.; Wong, George N.; Bower, Geoffrey C.; Broderick, Avery E.; Chael, Andrew; Chatterjee, Koushik; Gammie, Charles F.; Georgiev, Boris; Hada, Kazuhiro Loinard, Laurent; Markoff, Sera; Marrone, Daniel P.; Plambeck, Richard; Weintroub, Jonathan; Dexter, Matthew; MacMahon, David H. E.; Wright, Melvyn; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barausse, Enrico; Barrett, John; Bintley, Dan; Boland, Wilfred; Bouman, Katherine L.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; Laurentis, Mariafelicia De; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dzib, Sergio A.; Eatough, Ralph P.; Falcke, Heino; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; García, Roberto; Gentaz, Olivier; Goddi, Ciriaco; Gold, Roman; Gómez, José L.; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jorstad, Svetlana; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Jae-Young; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Lonsdale, Colin; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Müller, Cornelia; Musoke, Gibwa; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Savolainen, Tuomas; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; Bemmel, Ilse van; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Ward-Thompson, Derek; Wex, Norbert; Wharton, Robert; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan.-- Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI., The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature- A ring with azimuthal brightness asymmetry- A nd to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009-2017 to be consistent with a persistent asymmetric ring of ∼40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin. © 2020 The Author(s). Published by the American Astronomical Society., The authors of the present paper thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt projects 1171506 and 3190878, BASAL AFB-170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico-Universidad Nacional Autonoma de Mexico (DGAPA-UNAM, project IN112417); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649 and Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. , for NASA, under contract NAS5-26555); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1312651, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants PGC2018-098915-B-C21, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation program under grant agreement No. 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X; the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario. ca), Calcul Quebec (http://www.calculquebec.ca), and Compute Canada (http://www.computecanada.ca). We thank the staff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with the National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrofisica, ptica, y Electronica (Mexico), and the University of Massachusetts at Amherst (USA). The IRAM 30 m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany), and IGN (Instituto Geografico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the National Science Foundation through grant PLR- 1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation, and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under an open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with hydrogen masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people.

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2020
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38. First M87 Event Horizon Telescope Results. III. Data Processing and Calibration

Author

Robert Wharton, Tuomas Savolainen, Neil M. Nagar, Qingwen Wu, Chunchong Ni, Jason SooHoo, Arash Roshanineshat, Roger Brissenden, Mahito Sasada, Ramesh Narayan, Heino Falcke, Garrett K. Keating, Buell T. Jannuzi, John E. Carlstrom, John Conway, Michael Kramer, Oliver Porth, Tod R. Lauer, Iniyan Natarajan, Ilje Cho, Lia Medeiros, C. Y. Kuo, Eduardo Ros, Olivier Gentaz, David J. James, Carsten Kramer, Jirong Mao, Colin J. Lonsdale, Jan Wagner, Ed Fomalont, Jae-Young Kim, Makoto Inoue, Karl M. Menten, Aristeidis Noutsos, Ziyan Zhu, Zhiqiang Shen, Mariafelicia De Laurentis, Thomas P. Krichbaum, Ye-Fei Yuan, Chet Ruszczyk, Fumie Tazaki, Kuo Liu, Mark Kettenis, Alan P. Marscher, Joseph R. Farah, Dan Bintley, Minfeng Gu, Dominic W. Pesce, Roberto Neri, Lynn D. Matthews, Avery E. Broderick, Masanori Nakamura, Katherine L. Bouman, Charles F. Gammie, Huib Jan van Langevelde, Ming-Tang Chen, Taehyun Jung, Jordy Davelaar, Hiroshi Nagai, Vincent Piétu, Ben Prather, Shoko Koyama, Kotaro Moriyama, Sang-Sung Lee, Ziri Younsi, André Young, Christian M. Fromm, Cornelia Müller, Michael Janssen, Silke Britzen, J. Anton Zensus, Ue-Li Pen, Yosuke Mizuno, Monika Moscibrodzka, Thomas W. Folkers, Jason Dexter, Daniel R. van Rossum, Mel Rose, Izumi Mizuno, Tyler Trent, Vincent L. Fish, Keiichi Asada, Yi Chen, Michael Titus, Freek Roelofs, Des Small, Roman Gold, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, Satoki Matsushita, Karl Friedrich Schuster, Ronald Hesper, Rurik A. Primiani, Pierre Christian, Zheng Meyer-Zhao, Wu Jiang, Nicholas R. MacDonald, Gisela N. Ortiz-León, Pablo Torne, Daniel Michalik, Kazi L.J. Rygl, Mansour Karami, José L. Gómez, Paul Tiede, Venkatessh Ramakrishnan, Gopal Narayanan, Alexander W. Raymond, Wen Ping Lo, Luis C. Ho, Geoffrey C. Bower, James M. Moran, Bong Won Sohn, Ilse van Bemmel, Feryal Özel, Kamal Souccar, Paul T. P. Ho, Gregory Desvignes, Anne Kathrin Baczko, Zhiyuan Li, Feng Yuan, David H. Hughes, Ramesh Karuppusamy, Yuzhu Cui, Shiro Ikeda, John Wardle, Michael D. Johnson, Sascha Trippe, Junhan Kim, Tomohisa Kawashima, Jorge A. Preciado-López, Bart Ripperda, Dominique Broguiere, Ru-Sen Lu, Roger J. Cappallo, Hector Olivares, A. Nadolski, Jonathan Weintroub, Thomas Bronzwaer, Walter Alef, David Ball, Chi-kwan Chan, Laurent Loinard, Richard L. Plambeck, Roberto Garcia, Boris Georgiev, Koushik Chatterjee, R. P. Eatough, Shan Shan Zhao, Andrei P. Lobanov, Geoffrey B. Crew, George N. Wong, W. Boland, Mislav Baloković, David Sánchez-Arguelles, Ramprasad Rao, Michael Lindqvist, Guang-Yao Zhao, Shami Chatterjee, Patrick M. Koch, Kazuhiro Hada, Nicolas Pradel, Aleksandar Popstefanija, Sheperd S. Doeleman, Britton Jeter, Sera Markoff, Benjamin R. Ryan, Michael Bremer, Michael H. Hecht, S. Sánchez, Sara Issaoun, Norbert Wex, Nimesh A. Patel, Jessica Dempsey, Helge Rottmann, James M. Cordes, Elisabetta Liuzzo, Rebecca Azulay, Lei Huang, Svetlana G. Jorstad, Per Friberg, Hiroki Okino, Ciriaco Goddi, Andrew Chael, F. Peter Schloerb, Luciano Rezzolla, Jun Yi Koay, Jongsoo Kim, Shuichiro Tsuda, Daniel C. M. Palumbo, Mark Gurwell, Ivan Marti-Vidal, Hung Yi Pu, Tomoaki Oyama, Motoki Kino, Yan-Rong Li, John E. Barrett, Peter Galison, Alan E. E. Rogers, Dimitrios Psaltis, Mareki Honma, Daniel P. Marrone, Alan L. Roy, Kazunori Akiyama, Maciek Wielgus, Raquel Fraga-Encinas, Hiroaki Nishioka, Mark G. Rawlings, Laura Vertatschitsch, Remo P. J. Tilanus, Ken H. Young, Paul Yamaguchi, Lindy Blackburn, Roger Deane, Kenji Toma, Do-Young Byun, Antxon Alberdi, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Ministerio de Economía, Industria y Competitividad (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón, Gómez Fernández, J. L., Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Cappallo, R., Farah, J. R., Folkers, T. W., Meyer-Zhao, Z., Michalik, D., Nadolski, A., Nishioka, H., Pradel, N., Primiani, R. A., Souccar, K., Vertatschitsch, L., Yamaguchi, P., Alberdi, Antxón [0000-0002-9371-1033], Gómez Fernández, J. L. [0000-0003-4190-7613], Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, and Astronomy

Subjects
010504 meteorology & atmospheric sciences, galaxies: jet, Radio galaxy, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, galaxies: individual, General Relativity and Quantum Cosmology (gr-qc), Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: individual: M87, 01 natural sciences, Submillimeter Array, General Relativity and Quantum Cosmology, Techniques: high angular resolution, individual (M87, 3C279) [Galaxies], 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, Event Horizon Telescope, Supermassive black hole, 3C279, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Black hole physics, black hole physic, Astrophysics - Astrophysics of Galaxies, 3. Good health, high angular resolution [Techniques], Interferometry, Amplitude, Space and Planetary Science, Galaxies: jets, Astrophysics of Galaxies (astro-ph.GA), Techniques: interferometric, interferometric [Techniques], jets [Galaxies], Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Galaxies: individual (M87, 3C279), Radio wave
Abstract

We present the calibration and reduction of Event Horizon Telescope (EHT) 1.3 mm radio wavelength observations of the supermassive black hole candidate at the center of the radio galaxy M87 and the quasar 3C 279, taken during the 2017 April 5–11 observing campaign. These global very long baseline interferometric observations include for the first time the highly sensitive Atacama Large Millimeter/submillimeter Array (ALMA); reaching an angular resolution of 25 μas, with characteristic sensitivity limits of ~1 mJy on baselines to ALMA and ~10 mJy on other baselines. The observations present challenges for existing data processing tools, arising from the rapid atmospheric phase fluctuations, wide recording bandwidth, and highly heterogeneous array. In response, we developed three independent pipelines for phase calibration and fringe detection, each tailored to the specific needs of the EHT. The final data products include calibrated total intensity amplitude and phase information. They are validated through a series of quality assurance tests that show consistency across pipelines and set limits on baseline systematic errors of 2% in amplitude and 1° in phase. The M87 data reveal the presence of two nulls in correlated flux density at ~3.4 and ~8.3 Gλ and temporal evolution in closure quantities, indicating intrinsic variability of compact structure on a timescale of days, or several light-crossing times for a few billion solar-mass black hole. These measurements provide the first opportunity to image horizon-scale structure in M87.© 2019. The American Astronomical Society, The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

Published
2019
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39. First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring

Author

Michael Janssen, Joseph Neilsen, Gopal Narayanan, Alexander W. Raymond, Gregory Desvignes, Thomas Bronzwaer, Anne Kathrin Baczko, Alan E. E. Rogers, Ru-Sen Lu, Feryal Özel, Qingwen Wu, Shan Shan Zhao, Monika Moscibrodzka, Chunchong Ni, Michael Titus, Freek Roelofs, Buell T. Jannuzi, Tod R. Lauer, Wen Ping Lo, Geoffrey C. Bower, James M. Moran, Taehyun Jung, Bart Ripperda, Dominique Broguiere, Luciano Rezzolla, Jongsoo Kim, Jirong Mao, Jonathan Weintroub, Colin J. Lonsdale, Laurent Loinard, Daniel Michalik, John Conway, Nicholas R. MacDonald, Olivier Gentaz, Iniyan Natarajan, Izumi Mizuno, Vincent L. Fish, Eduardo Ros, Minfeng Gu, Ilse van Bemmel, Kotaro Moriyama, David J. James, Michael D. Johnson, Vincent Piétu, Daryl Haggard, Richard L. Plambeck, Lynn D. Matthews, Avery E. Broderick, Ilje Cho, Katherine L. Bouman, Karl Friedrich Schuster, Ronald Hesper, Zheng Meyer-Zhao, Daniel C. M. Palumbo, Roman Gold, Koushik Chatterjee, Bong Won Sohn, Makoto Inoue, Rebecca Azulay, Paul Tiede, Alan P. Marscher, Ziri Younsi, Ye-Fei Yuan, Jason Dexter, Venkatessh Ramakrishnan, Michael Lindqvist, Michael Bremer, Carsten Kramer, Ramesh Karuppusamy, Michael Kramer, Chi-kwan Chan, R. P. Eatough, Shiro Ikeda, Jan Wagner, Oliver Porth, Garrett K. Keating, Yi Chen, Tuomas Savolainen, Neil M. Nagar, Chet Ruszczyk, Per Friberg, Michael H. Hecht, Huib Jan van Langevelde, Alan L. Roy, Kazunori Akiyama, Jordy Davelaar, Sang-Sung Lee, Maciek Wielgus, Jason SooHoo, Lei Huang, Hiroshi Nagai, Keiichi Asada, David Ball, Thomas P. Krichbaum, A. Nadolski, Roger Brissenden, Mislav Baloković, Roberto Neri, Svetlana G. Jorstad, Des Small, Shami Chatterjee, Raquel Fraga-Encinas, Michael A. Nowak, Hiroaki Nishioka, Mark G. Rawlings, S. Sánchez, Dominic W. Pesce, Heino Falcke, Roberto Garcia, Luis C. Ho, Yan-Rong Li, Fumie Tazaki, Jessica Dempsey, Sera Markoff, David H. Hughes, Daniel R. van Rossum, Elisabetta Liuzzo, Christian M. Fromm, Cornelia Müller, Yuzhu Cui, Jun Yi Koay, Mahito Sasada, Geoffrey B. Crew, Norbert Wex, Nimesh A. Patel, Ed Fomalont, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, David Sánchez-Arguelles, Laura Vertatschitsch, Remo P. J. Tilanus, Andrew Chael, Shuichiro Tsuda, Dan Bintley, Ciriaco Goddi, Ramesh Narayan, Charles F. Gammie, Tyler Trent, Mel Rose, Feng Yuan, Satoki Matsushita, Robert Wharton, Jadyn Anczarski, F. Peter Schloerb, Patrick M. Koch, Kazi L.J. Rygl, Nicolas Pradel, Britton Jeter, Tomohisa Kawashima, Shuo Zhang, John E. Carlstrom, Jae-Young Kim, Junhan Kim, Arash Roshanineshat, Jorge A. Preciado-López, Benjamin R. Ryan, Sara Issaoun, Hector Olivares, Andreas Eckart, Hiroki Okino, Karl M. Menten, Lia Medeiros, Zhiqiang Shen, Mariafelicia De Laurentis, Kuo Liu, Joseph R. Farah, Aristeidis Noutsos, Mark Kettenis, C. Y. Kuo, Wu Jiang, Zhiyuan Li, Boris Georgiev, W. Boland, Ramprasad Rao, Guang-Yao Zhao, Ming-Tang Chen, Mansour Karami, José L. Gómez, André Young, Pablo Torne, John Wardle, Ben Prather, Shoko Koyama, Rurik A. Primiani, Pierre Christian, Walter Alef, Kamal Souccar, Paul T. P. Ho, Andrei P. Lobanov, George N. Wong, Kazuhiro Hada, Ziyan Zhu, Silke Britzen, J. Anton Zensus, Ue-Li Pen, Yosuke Mizuno, Sascha Trippe, Sheperd S. Doeleman, James M. Cordes, John E. Barrett, Peter Galison, Dimitrios Psaltis, Mareki Honma, Daniel P. Marrone, Masanori Nakamura, Frederick K. Baganoff, Aleksandar Popstefanija, Helge Rottmann, Mark Gurwell, Ivan Marti-Vidal, Hung Yi Pu, Tomoaki Oyama, Motoki Kino, Roger Deane, Ken H. Young, Paul Yamaguchi, Lindy Blackburn, Kenji Toma, Do-Young Byun, Antxon Alberdi, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía, Industria y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japan Society for the Promotion of Science, Japanese Government, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, National Research Foundation of Korea, Netherlands Organization for Scientific Research, Natural Sciences and Engineering Research Council of Canada, Russian Science Foundation, National Research Foundation (South Africa), Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón, Gómez Fernández, J. L., Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Anczarski, J., Baganoff, F. K., Eckart, A., Farah, J. R., Haggard, D., Meyer-Zhao, Z., Michalik, D., Nadolski, A., Neilsen, J., Nishioka, H., Nowak, M. A., Pradel, N., Primiani, R. A., Souccar, K., Vertatschitsch, L., Yamaguchi, P., Zhang, S., Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Alberdi, Antxón [0000-0002-9371-1033], and Gómez Fernández, J. L. [0000-0003-4190-7613]

Subjects
Magnetohydrodynamics (MHD), 010504 meteorology & atmospheric sciences, individual (M87) [galaxies], Event horizon, galaxies: jet, Astronomy, Strong gravitational lensing, black hole physics, jets [galaxies], galaxies: individual, Astrophysics, accretion, accretion disk, 01 natural sciences, General Relativity and Quantum Cosmology, Galaxies: individual (M87), accretion, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, accretion, accretion disks, accretion disks, high angular resolution [techniques], Accretion disks, (MHD), Astrophysics - High Energy Astrophysical Phenomena, General relativity, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Compact star, galaxies: individual: M87, magnetohydrodynamics (MHD), Techniques: high angular resolution, 0103 physical sciences, (M87), 0105 earth and related environmental sciences, Event Horizon Telescope, Supermassive black hole, Astronomy and Astrophysics, Black hole physics, Astrophysics - Astrophysics of Galaxies, black hole physic, Black hole, Rotating black hole, Space and Planetary Science, magnetohydrodynamics: MHD, Galaxies: jets, Astrophysics of Galaxies (astro-ph.GA), magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Event Horizon Telescope (EHT) has mapped the central compact radio source of the elliptical galaxy M87 at 1.3 mm with unprecedented angular resolution. Here we consider the physical implications of the asymmetric ring seen in the 2017 EHT data. To this end, we construct a large library of models based on general relativistic magnetohydrodynamic (GRMHD) simulations and synthetic images produced by general relativistic ray tracing. We compare the observed visibilities with this library and confirm that the asymmetric ring is consistent with earlier predictions of strong gravitational lensing of synchrotron emission from a hot plasma orbiting near the black hole event horizon. The ring radius and ring asymmetry depend on black hole mass and spin, respectively, and both are therefore expected to be stable when observed in future EHT campaigns. Overall, the observed image is consistent with expectations for the shadow of a spinning Kerr black hole as predicted by general relativity. If the black hole spin and M87's large scale jet are aligned, then the black hole spin vector is pointed away from Earth. Models in our library of non-spinning black holes are inconsistent with the observations as they do not produce sufficiently powerful jets. At the same time, in those models that produce a sufficiently powerful jet, the latter is powered by extraction of black hole spin energy through mechanisms akin to the Blandford-Znajek process. We briefly consider alternatives to a black hole for the central compact object. Analysis of existing EHT polarization data and data taken simultaneously at other wavelengths will soon enable new tests of the GRMHD models, as will future EHT campaigns at 230 and 345 GHz.© 2019. The American Astronomical Society., The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

Published
2019
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40. First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

Author

Taehyun Jung, Kotaro Moriyama, Charles F. Gammie, John Conway, Eduardo Ros, Jason Dexter, Svetlana G. Jorstad, Iniyan Natarajan, Kenji Toma, Do-Young Byun, Antxon Alberdi, Ilje Cho, Ye-Fei Yuan, Michael Titus, Freek Roelofs, Jun Yi Koay, Zhiqiang Shen, Mariafelicia De Laurentis, Kuo Liu, Makoto Inoue, Dan Bintley, Ed Fomalont, Shuichiro Tsuda, Michael Bremer, Izumi Mizuno, Mansour Karami, José L. Gómez, Vincent L. Fish, Michael Kramer, Oliver Porth, Sara Issaoun, Roger Deane, Jason SooHoo, Michael Janssen, Paul Tiede, Shiro Ikeda, André Young, Mel Rose, Thomas P. Krichbaum, William T. Freeman, Wen Ping Lo, Geoffrey C. Bower, James M. Moran, Qingwen Wu, Chunchong Ni, Bart Ripperda, Dominique Broguiere, Jirong Mao, Masanori Nakamura, Dominic W. Pesce, Colin J. Lonsdale, Buell T. Jannuzi, Huib Jan van Langevelde, R. P. Eatough, Pablo Torne, Olivier Gentaz, David H. Hughes, Tuomas Savolainen, Neil M. Nagar, Tod R. Lauer, Keiichi Asada, John Wardle, Des Small, Daniel R. van Rossum, Tomohisa Kawashima, Patrick M. Koch, Boris Georgiev, Nicolas Pradel, Britton Jeter, David J. James, A. Nadolski, Monika Moscibrodzka, Fumie Tazaki, Ken H. Young, Paul Yamaguchi, Richard L. Plambeck, Karl Friedrich Schuster, Ronald Hesper, Koushik Chatterjee, Aleksandar Popstefanija, S. Sánchez, Zheng Meyer-Zhao, W. Boland, Ramprasad Rao, Jessica Dempsey, Alan P. Marscher, Helge Rottmann, John E. Carlstrom, Elisabetta Liuzzo, Michael Lindqvist, Guang-Yao Zhao, Lia Medeiros, Ramesh Karuppusamy, Rebecca Azulay, Roberto Neri, Chet Ruszczyk, C. Y. Kuo, Garrett K. Keating, Nicholas R. MacDonald, Jae-Young Kim, Per Friberg, Lindy Blackburn, Tyler Trent, F. Peter Schloerb, Chi-kwan Chan, Mark Gurwell, Jonathan Weintroub, Joseph R. Farah, Satoki Matsushita, Ming-Tang Chen, Ivan Marti-Vidal, Ben Prather, Luis C. Ho, Kazi L.J. Rygl, Shoko Koyama, Benjamin R. Ryan, Hung Yi Pu, Laurent Loinard, Rurik A. Primiani, Pierre Christian, Sang-Sung Lee, Jorge A. Preciado-López, Bong Won Sohn, Wu Jiang, Karl M. Menten, Tomoaki Oyama, Feryal Özel, Hector Olivares, Motoki Kino, Michael H. Hecht, Alan E. E. Rogers, Zhiyuan Li, Aristeidis Noutsos, Hiroki Okino, Lei Huang, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, John E. Barrett, Yuzhu Cui, Mark Kettenis, Peter Galison, Andrew Chael, Kamal Souccar, Christian M. Fromm, Cornelia Müller, Paul T. P. Ho, Luciano Rezzolla, Dimitrios Psaltis, Mareki Honma, Daniel P. Marrone, Jongsoo Kim, Daniel C. M. Palumbo, Gopal Narayanan, Alexander W. Raymond, Gregory Desvignes, Anne Kathrin Baczko, Yan-Rong Li, Lynn D. Matthews, Avery E. Broderick, Robert Wharton, Ru-Sen Lu, Feng Yuan, Ziri Younsi, Minfeng Gu, Arash Roshanineshat, Junhan Kim, Katherine L. Bouman, Yi Chen, Heino Falcke, Alan L. Roy, Kazunori Akiyama, Maciek Wielgus, Raquel Fraga-Encinas, Hiroaki Nishioka, Mark G. Rawlings, Walter Alef, Laura Vertatschitsch, Remo P. J. Tilanus, Sera Markoff, Andrei P. Lobanov, George N. Wong, Norbert Wex, Kazuhiro Hada, Thomas Bronzwaer, Nimesh A. Patel, Ziyan Zhu, Silke Britzen, J. Anton Zensus, Ue-Li Pen, Yosuke Mizuno, Ciriaco Goddi, Sascha Trippe, Shan Shan Zhao, Sheperd S. Doeleman, Mislav Baloković, Shami Chatterjee, Carsten Kramer, Vincent Piétu, Jan Wagner, James M. Cordes, Roman Gold, Venkatessh Ramakrishnan, Jordy Davelaar, Hiroshi Nagai, Daniel Michalik, Ilse van Bemmel, Michael D. Johnson, David Ball, Roberto Garcia, Geoffrey B. Crew, David Sánchez-Arguelles, Roger Brissenden, Mahito Sasada, Ramesh Narayan, Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Farah, J. R., Meyer-Zhao, Z., Michalik, D., Nadolski, A., Nishioka, H., Pradel, N., Primiani, R. A., Souccar, K., Vertatschitsch, L., Yamaguchi, P., Astronomy, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón [0000-0002-9371-1033], Gómez Fernández, J. L. [0000-0003-4190-7613], Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, Alberdi, Antxón, and Gómez Fernández, J. L.

Subjects
Brightness, 010504 meteorology & atmospheric sciences, galaxies: jet, Astronomy, black hole physics, FOS: Physical sciences, galaxies: individual, techniques: image processing, Astrophysics, General Relativity and Quantum Cosmology (gr-qc), galaxies: individual: M87, 01 natural sciences, Synthetic data, General Relativity and Quantum Cosmology, galaxies: individual (M87), 0103 physical sciences, image processing [Techniques], 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Event Horizon Telescope, Physics, Ground truth, Supermassive black hole, techniques: high angular resolution, Astronomy and Astrophysics, Black hole physics, galaxies: jets, individual (M87) [Galaxies], Astrophysics - Astrophysics of Galaxies, black hole physic, 3. Good health, Orbit, Interferometry, high angular resolution [Techniques], Space and Planetary Science, techniques: interferometric, Astrophysics of Galaxies (astro-ph.GA), interferometric [Techniques], jets [Galaxies], Deconvolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ~40 μas, consistent with the size and shape of the lensed photon orbit encircling the "shadow" of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others' work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use when reconstructing images of M87. Across all tests in both stages, the ring diameter and asymmetry remained stable, insensitive to the choice of imaging technique. We describe the EHT imaging procedures, the primary image features in M87, and the dependence of these features on imaging assumptions.© 2019. The American Astronomical Society., The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

Published
2019
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41. First M87 Event Horizon Telescope Results. I. the Shadow of the Supermassive Black Hole

Author

Olivier Gentaz, David J. James, Hector Olivares, John E. Barrett, Alan P. Marscher, C. M. Violette Impellizzeri, Peter Oshiro, Peter Galison, Tyler Trent, Sang-Sung Lee, Arturo I. Gómez-Ruiz, Satoki Matsushita, Carsten Kramer, Scott Paine, Dimitrios Psaltis, Mareki Honma, Kazi L.J. Rygl, Shuo Zhang, Jan Wagner, Daniel P. Marrone, Ryan Chilson, Jorge A. Preciado-López, Christopher Beaudoin, Sara Issaoun, André Young, A. A. Stark, Jordy Davelaar, Hiroshi Nagai, Zhiqiang Shen, Pablo Torne, Chris Eckert, John Wardle, Ranjani Srinivasan, David M. Gale, David Ball, Alan L. Roy, Lupin C.C. Lin, Thomas Bronzwaer, Kazunori Akiyama, W. B. Everett, Li Ming Lu, Ta Shun Wei, Sheperd S. Doeleman, Shu Hao Chang, Roberto Garcia, Richard L. Plambeck, Maciek Wielgus, Iniyan Natarajan, Raquel Fraga-Encinas, Hiroaki Nishioka, Mark G. Rawlings, Tirupati K. Sridharan, Geoffrey B. Crew, Vernon Fath, Michael H. Hecht, Frederic Gueth, Jun Yi Koay, David Sánchez-Arguelles, Chih Chiang Han, Michael Kramer, Mariafelicia De Laurentis, Kuo Liu, Oliver Porth, Jae-Young Kim, Ilje Cho, Shan Shan Zhao, Hotaka Shiokawa, Martin P. McColl, Song Chu Chang, Lei Huang, William Stahm, Makoto Inoue, Svetlana G. Jorstad, Andrew Chael, Chih Cheng Chang, Thomas P. Krichbaum, Dominic W. Pesce, Chung Chen Chen, Laura Vertatschitsch, Jonathan Weintroub, Alejandro F. Sáez-Madain, Sera Markoff, Shuichiro Tsuda, Ryan Berthold, Chao-Te Li, M. C. H. Wright, Daniel R. van Rossum, J. Peñalver, Neal R. Erickson, Remo P. J. Tilanus, John E. Carlstrom, Roger Deane, Minfeng Gu, Michael Titus, Laurent Loinard, Lia Medeiros, C. Y. Kuo, Iain Coulson, Michael Janssen, Ben Prather, Katherine L. Bouman, Lucy M. Ziurys, Norbert Wex, Freek Roelofs, Feng Gao, Yau De Huang, Dan Bintley, N. W. Halverson, Benjamin R. Ryan, Nimesh A. Patel, Aaron Faber, Mansour Karami, Robert Freund, Ming-Tang Chen, K. T. Story, Gertie Geertsema, Daryl Haggard, Paul Shaw, Ronald Grosslein, S. A. Dzib, Joseph Crowley, Kuo Chang Han, Shoko Koyama, José L. Gómez, Chet Ruszczyk, David R. Smith, Michael Bremer, Daniel Michalik, James Hoge, Karl M. Menten, Juan-Carlos Algaba, Aristeidis Noutsos, William Snow, Thomas W. Folkers, Masanori Nakamura, Homin Jiang, James M. Cordes, Uwe Bach, Christopher Risacher, Rurik A. Primiani, Pierre Christian, David H. Hughes, Wen Ping Lo, Geoffrey C. Bower, James M. Moran, Ciriaco Goddi, Yi Chen, Christopher Greer, Roger J. Cappallo, Ilse van Bemmel, Andreas Eckart, Ziyan Zhu, Chi H. Nguyen, Rubén Herrero-Illana, Robert Wharton, Antonio Hernández-Gómez, Bart Ripperda, Dominique Broguiere, Pim Schellart, Mark Derome, Chih-Wei Locutus Huang, Chen Yu Yu, Kuan Yu Liu, Lijing Shao, Christiaan D. Brinkerink, Michael D. Johnson, Mark Kettenis, Michael Lindqvist, Frederick K. Baganoff, John Conway, Remi Sassella, Nathan Whitehorn, Eduardo Ros, David P. Woody, Jessica Dempsey, Gopal Narayanan, Elisabetta Liuzzo, Akihiko Hirota, D. A. Graham, Hiroki Okino, Vincent Piétu, Alexander W. Raymond, Gregory Desvignes, Anne Kathrin Baczko, Arash Roshanineshat, Kevin M. Silva, Timothy Norton, Heino Falcke, Aleksandar Popstefanija, Ken H. Young, Per Friberg, Paul Yamaguchi, Derek Kubo, E. Castillo-Domínguez, Jason W. Henning, R. Laing, Kimihiro Kimura, Rodrigo Córdova Rosado, Roman Gold, Helge Rottmann, Silke Britzen, J. Anton Zensus, Roger Brissenden, Ru-Sen Lu, Ye-Fei Yuan, F. Peter Schloerb, Stephen R. McWhirter, Joseph R. Farah, Ue-Li Pen, Yosuke Mizuno, Charles F. Gammie, Mel Rose, Harriet Parsons, Venkatessh Ramakrishnan, Philippe Raffin, Ignacio Ruiz, Mahito Sasada, Kamal Souccar, Joseph Neilsen, J. G. A. Wouterloot, Jirong Mao, Colin J. Lonsdale, Feng Yuan, Jadyn Anczarski, Lindy Blackburn, N. Phillips, Don Sousa, Ramesh Narayan, Alan R. Whitney, Paul T. P. Ho, Kyle D. Massingill, Patrick M. Koch, Taehyun Jung, Erik M. Leitch, Junhan Kim, Nicolas Pradel, Kevin A. Dudevoir, Britton Jeter, Jason SooHoo, Tomohisa Kawashima, T. M. Crawford, Mark Gurwell, A. Montaña, R. P. Eatough, Sascha Trippe, Ivan Marti-Vidal, Dirk Muders, Craig Walther, Atish Kamble, Qingwen Wu, Chunchong Ni, George Nystrom, Yusuke Kono, Ryan Keisler, Huib Jan van Langevelde, Stefan Heyminck, Kenji Toma, Do-Young Byun, Sjoerd T. Timmer, Antxon Alberdi, Hung Yi Pu, Hugo Messias, Feryal Özel, Kotaro Moriyama, John David, M. Poirier, Mislav Baloković, Fumie Tazaki, Keiichi Asada, S. Sánchez, Wu Jiang, Tomoaki Oyama, Shami Chatterjee, Des Small, Richard Lacasse, Ray Blundell, Motoki Kino, Michael A. Nowak, Jason Dexter, Walter Alef, Jinchi Hao, Zhiyuan Li, Garrett K. Keating, Christian M. Fromm, Cornelia Müller, Ching Tang Liu, Alexandra S. Rahlin, William Montgomerie, Andrei P. Lobanov, Bradford Benson, George N. Wong, Kazuhiro Hada, Sven Dornbusch, George Reiland, Boris Georgiev, Luciano Rezzolla, Jongsoo Kim, W. Boland, Ramprasad Rao, Guang-Yao Zhao, Buell T. Jannuzi, Sandra Bustamente, Daniel C. M. Palumbo, Tod R. Lauer, Karl Friedrich Schuster, Ronald Hesper, Zheng Meyer-Zhao, John Kuroda, Ramesh Karuppusamy, Pierre Martin-Cocher, Chi-kwan Chan, Timothy C. Chuter, Izumi Mizuno, Vincent L. Fish, Yutaka Hasegawa, Roberto Neri, Matthew R. Dexter, Paul Tiede, Rodrigo Amestica, S. Navarro, William T. Freeman, Callie Matulonis, Luis C. Ho, Hideo Ogawa, Shiro Ikeda, Ralph G. Marson, A. Nadolski, J. Blanchard, Ed Fomalont, Monika Moscibrodzka, Nicholas R. MacDonald, Gisela N. Ortiz-León, Bong Won Sohn, David C. Forbes, Lynn D. Matthews, Avery E. Broderick, Ziri Younsi, Tuomas Savolainen, Neil M. Nagar, Alexander Allardi, M. Mora-Klein, Yuzhu Cui, Yan-Rong Li, Koushik Chatterjee, Rebecca Azulay, M. Zeballos, Alan E. E. Rogers, Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Bemmel, I. V., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, K., Young, A., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Algaba, J. -C., Allardi, A., Amestica, R., Anczarski, J., Bach, U., Baganoff, F. K., Beaudoin, C., Benson, B. A., Berthold, R., Blanchard, J. M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Dominguez, E., Chang, C. -C., Chang, S. -H., Chang, S. -C., Chen, C. -C., Chilson, R., Chuter, T. C., Rosado, R. C., Coulson, I. M., Crawford, T. M., Crowley, J., David, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K. A., Dzib, S. A., Eckart, A., Eckert, C., Erickson, N. R., Everett, W. B., Faber, A., Farah, J. R., Fath, V., Folkers, T. W., Forbes, D. C., Freund, R., Gomez-Ruiz, A. I., Gale, D. M., Gao, F., Geertsema, G., Graham, D. A., Greer, C. H., Grosslein, R., Gueth, F., Haggard, D., Halverson, N. W., Han, C. -C., Han, K. -C., Hao, J., Hasegawa, Y., Henning, J. W., Hernandez-Gomez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y. -D., Impellizzeri, C. M. V., Jiang, H., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R. A., Leitch, E. M., Li, C. -T., Lin, L. C. -C., Liu, C. -T., Liu, K. -Y., Lu, L. -M., Marson, R. G., Martin-Cocher, P. L., Massingill, K. D., Matulonis, C., Mccoll, M. P., Mcwhirter, S. R., Messias, H., Meyer-Zhao, Z., Michalik, D., Montana, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Neilsen, J., Nguyen, C. H., Nishioka, H., Norton, T., Nowak, M. A., Nystrom, G., Ogawa, H., Oshiro, P., Parsons, H., Paine, S. N., Penalver, J., Phillips, N. M., Poirier, M., Pradel, N., Primiani, R. A., Raffin, P. A., Rahlin, A. S., Reiland, G., Risacher, C., Ruiz, I., Saez-Madain, A. F., Sassella, R., Schellart, P., Shaw, P., Silva, K. M., Shiokawa, H., Smith, D. R., Snow, W., Souccar, K., Sousa, D., Sridharan, T. K., Srinivasan, R., Stahm, W., Stark, A. A., Story, K., Timmer, S. T., Vertatschitsch, L., Walther, C., Wei, T. -S., Whitehorn, N., Whitney, A. R., Woody, D. P., Wouterloot, J. G. A., Wright, M., Yamaguchi, P., Yu, C. -Y., Zeballos, M., Zhang, S., Ziurys, L., Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Event Horizon Telescope, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón, Gómez Fernández, J. L., Alberdi, Antxón [0000-0002-9371-1033], Gómez Fernández, J. L. [0000-0003-4190-7613], Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Gravitation and Astroparticle Physics Amsterdam

Subjects
010504 meteorology & atmospheric sciences, individual (M87) [galaxies], Event horizon, Astronomy, black hole physics, jets [galaxies], galaxies: individual, Astrophysics, high-resolution, 7. Clean energy, 01 natural sciences, Photon sphere, General Relativity and Quantum Cosmology, accretion, sagittarius-a-asterisk, 010303 astronomy & astrophysics, galactic-center, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, radio-sources, accretion disks, Galactic Center, grmhd simulations, 3. Good health, energy-distributions, active [galaxies], Anatomy, Astrophysics - High Energy Astrophysical Phenomena, Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: individual: M87, galaxies: individual (M87), Cell and Developmental Biology, 0103 physical sciences, (M87), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Event Horizon Telescope, Supermassive black hole, ghz vlbi observations, faraday-rotation, Astronomy and Astrophysics, galaxies: jets, Astrophysics - Astrophysics of Galaxies, Black hole, Rotating black hole, Space and Planetary Science, gravitation, Astrophysics of Galaxies (astro-ph.GA), advection-dominated accretion, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ionized-gas
Abstract

When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 ± 3 μas, which is circular and encompasses a central depression in brightness with a flux ratio 10:1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5 ± 0.7) × 109 Me. Our radiowave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible.© 2019. The American Astronomical Society, The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

Published
2019
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42. First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

Author

Tyler Trent, Vincent Piétu, Wen Ping Lo, Geoffrey C. Bower, James M. Moran, Jirong Mao, Daniel Michalik, Colin J. Lonsdale, Satoki Matsushita, Bart Ripperda, Dominique Broguiere, Roman Gold, Ilse van Bemmel, Kazi L.J. Rygl, Michael Bremer, Alan L. Roy, Kazunori Akiyama, Venkatessh Ramakrishnan, John Conway, Lynn D. Matthews, Avery E. Broderick, Michael D. Johnson, Minfeng Gu, Jessica Dempsey, Elisabetta Liuzzo, Ziri Younsi, Yuzhu Cui, Katherine L. Bouman, Maciek Wielgus, Sara Issaoun, Jorge A. Preciado-López, Michael Kramer, Raquel Fraga-Encinas, Hiroaki Nishioka, Eduardo Ros, Olivier Gentaz, Masanori Nakamura, Mark G. Rawlings, Tuomas Savolainen, Neil M. Nagar, F. Peter Schloerb, Oliver Porth, Benjamin R. Ryan, Dan Bintley, Koushik Chatterjee, David J. James, Kenji Toma, Do-Young Byun, Antxon Alberdi, Patrick M. Koch, Zhiqiang Shen, Mariafelicia De Laurentis, Kuo Liu, Thomas P. Krichbaum, Dominic W. Pesce, Roger Brissenden, Yi Chen, Nicolas Pradel, Jonathan Weintroub, Britton Jeter, Daniel R. van Rossum, Rebecca Azulay, Thomas Bronzwaer, Aleksandar Popstefanija, Ed Fomalont, Alan P. Marscher, Mansour Karami, José L. Gómez, Laurent Loinard, Mahito Sasada, Helge Rottmann, Sheperd S. Doeleman, Hiroki Okino, Richard L. Plambeck, Ye-Fei Yuan, Chet Ruszczyk, David H. Hughes, Iniyan Natarajan, Boris Georgiev, Karl Friedrich Schuster, Ronald Hesper, Laura Vertatschitsch, Remo P. J. Tilanus, Mislav Baloković, Zheng Meyer-Zhao, Sang-Sung Lee, Roger Deane, Ramesh Narayan, Michael H. Hecht, Heino Falcke, Svetlana G. Jorstad, Michael Lindqvist, John E. Barrett, Jae-Young Kim, Robert Wharton, Shami Chatterjee, Ilje Cho, Ben Prather, R. P. Eatough, Shan Shan Zhao, Makoto Inoue, Peter Galison, Ramesh Karuppusamy, W. Boland, Per Friberg, Alan E. E. Rogers, Ramprasad Rao, Gopal Narayanan, S. Sánchez, Alexander W. Raymond, Gregory Desvignes, Shoko Koyama, Arash Roshanineshat, Rurik A. Primiani, Pierre Christian, Carsten Kramer, Lei Huang, David Ball, Anne Kathrin Baczko, Izumi Mizuno, Guang-Yao Zhao, Sera Markoff, Chih-Wei Locutus Huang, Vincent L. Fish, Jan Wagner, Lijing Shao, Christiaan D. Brinkerink, James M. Cordes, Dimitrios Psaltis, Mareki Honma, Daniel P. Marrone, Mel Rose, Ru-Sen Lu, Karl M. Menten, Chi-kwan Chan, Jason SooHoo, Roberto Garcia, Aristeidis Noutsos, Joseph R. Farah, Qingwen Wu, Chunchong Ni, Monika Moscibrodzka, Hector Olivares, Ken H. Young, Paul Tiede, Walter Alef, Mark Gurwell, Ivan Marti-Vidal, Tomohisa Kawashima, Paul Yamaguchi, Norbert Wex, Nimesh A. Patel, Michael Janssen, Jordy Davelaar, Hiroshi Nagai, Andrew Chael, Taehyun Jung, Jun Yi Koay, Mark Kettenis, Hung Yi Pu, Kamal Souccar, Geoffrey B. Crew, Luciano Rezzolla, David Sánchez-Arguelles, Jongsoo Kim, Feryal Özel, Wu Jiang, Daniel C. M. Palumbo, Tomoaki Oyama, Andrei P. Lobanov, Fumie Tazaki, Feng Yuan, Ciriaco Goddi, Junhan Kim, André Young, Lindy Blackburn, Paul T. P. Ho, George N. Wong, Kotaro Moriyama, Shuichiro Tsuda, Motoki Kino, Zhiyuan Li, Nicholas R. MacDonald, Michael Titus, Roberto Neri, Kazuhiro Hada, Charles F. Gammie, Luis C. Ho, Freek Roelofs, Pablo Torne, Ziyan Zhu, Jason Dexter, John Wardle, Garrett K. Keating, Bong Won Sohn, Silke Britzen, J. Anton Zensus, Ue-Li Pen, Yosuke Mizuno, Huib Jan van Langevelde, Christian M. Fromm, Yan-Rong Li, Cornelia Müller, John E. Carlstrom, Shiro Ikeda, Sascha Trippe, Lia Medeiros, C. Y. Kuo, Buell T. Jannuzi, Ming-Tang Chen, Tod R. Lauer, A. Nadolski, Keiichi Asada, Des Small, Astronomy, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, High Energy Astrophys. & Astropart. Phys (API, FNWI), Gravitation and Astroparticle Physics Amsterdam, Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía, Industria y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón, Gómez Fernández, J. L., Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Alberdi, Antxón [0000-0002-9371-1033], Gómez Fernández, J. L. [0000-0003-4190-7613], Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Farah, J. R., Meyer-Zhao, Z., Michalik, D., Nadolski, A., Nishioka, H., Pradel, N., Primiani, R. A., Souccar, K., Vertatschitsch, L., and Yamaguchi, P.

Subjects
010504 meteorology & atmospheric sciences, individual (M87) [galaxies], Event horizon, General relativity, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, black hole physics, FOS: Physical sciences, galaxies: individual, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, General Relativity and Quantum Cosmology (gr-qc), galaxies: individual: M87, 01 natural sciences, 7. Clean energy, General Relativity and Quantum Cosmology, galaxies: individual (M87), Gravitation, 0103 physical sciences, (M87), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Event Horizon Telescope, High Energy Astrophysical Phenomena (astro-ph.HE), high angular resolution [techniques], techniques: high angular resolution, Astronomy and Astrophysics, black hole physic, Astrophysics - Astrophysics of Galaxies, Galaxy, interferometric [techniques], Black hole, Rotating black hole, Space and Planetary Science, gravitation, techniques: interferometric, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, Schwarzschild radius
Abstract

We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using two independent sampling algorithms that consider distinct representations of the visibility data. We show that the crescent family of models is statistically preferred over other comparably complex geometric models that we explore. We calibrate the geometric model parameters using general relativistic magnetohydrodynamic (GRMHD) models of the emission region and estimate physical properties of the source. We further fit images generated from GRMHD models directly to the data. We compare the derived emission region and black hole parameters from these analyses with those recovered from reconstructed images. There is a remarkable consistency among all methods and data sets. We find that >50% of the total flux at arcsecond scales comes from near the horizon, and that the emission is dramatically suppressed interior to this region by a factor >10, providing direct evidence of the predicted shadow of a black hole. Across all methods, we measure a crescent diameter of 42 ± 3 μas and constrain its fractional width to be, The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

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2019
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43. First M87 Event Horizon Telescope Results. II. Array and Instrumentation

Author

Monika Moscibrodzka, Elisabetta Liuzzo, F. Peter Schloerb, John Conway, Remi Sassella, Eduardo Ros, Kevin M. Silva, Christopher Beaudoin, Minfeng Gu, Stephen R. McWhirter, Nicholas R. MacDonald, Derek Kubo, E. Castillo-Domínguez, Iain Coulson, Katherine L. Bouman, John E. Barrett, Peter Oshiro, Peter Galison, Walter Alef, Ignacio Ruiz, N. Phillips, Gisela N. Ortiz-León, Ye-Fei Yuan, Arturo I. Gómez-Ruiz, Scott Paine, Dimitrios Psaltis, Mareki Honma, Juan-Carlos Algaba, Daniel P. Marrone, Alexandra S. Rahlin, Li Ming Lu, Iniyan Natarajan, Thomas W. Folkers, Zhiqiang Shen, Mariafelicia De Laurentis, Kuo Liu, Chao-Te Li, M. C. H. Wright, Mansour Karami, José L. Gómez, Roger J. Cappallo, Roger Deane, Lucy M. Ziurys, Yi Chen, Christopher Greer, William Montgomerie, Andrei P. Lobanov, George N. Wong, Bong Won Sohn, Huib Jan van Langevelde, Mark Gurwell, Ivan Marti-Vidal, Ilje Cho, Hotaka Shiokawa, Martin P. McColl, Makoto Inoue, Shu Hao Chang, K. T. Story, Joseph Crowley, C. M.Violette Impellizzeri, Kazuhiro Hada, Michael Kramer, Ranjani Srinivasan, David Ball, Keiichi Asada, Des Small, Hung Yi Pu, John David, Tomoaki Oyama, Svetlana G. Jorstad, Boris Georgiev, Sheperd S. Doeleman, Oliver Porth, Nathan Whitehorn, Alan L. Roy, Kazunori Akiyama, W. B. Everett, Maciek Wielgus, Don Sousa, J. Blanchard, Ray Blundell, Motoki Kino, Karl Friedrich Schuster, Ronald Hesper, Zheng Meyer-Zhao, John Kuroda, Heino Falcke, Chung Chen Chen, Carsten Kramer, Thomas P. Krichbaum, R. P. Eatough, S. Sánchez, Roberto Garcia, Jan Wagner, Ramesh Karuppusamy, Raquel Fraga-Encinas, Hiroaki Nishioka, Mark G. Rawlings, Ed Fomalont, W. Boland, Ramprasad Rao, Timothy Norton, Ching Tang Liu, James M. Cordes, Bradford Benson, Dominic W. Pesce, Yan-Rong Li, Geoffrey B. Crew, Vernon Fath, Frederic Gueth, David Sánchez-Arguelles, Roger Brissenden, Chi-kwan Chan, Timothy C. Chuter, Qingwen Wu, Chunchong Ni, Yuzhu Cui, Guang-Yao Zhao, Harriet Parsons, Ken H. Young, Paul Yamaguchi, Mahito Sasada, Daniel R. van Rossum, Yusuke Kono, Ryan Keisler, Masanori Nakamura, Patrick M. Koch, Nicolas Pradel, Ramesh Narayan, Rodrigo Córdova Rosado, Jordy Davelaar, Hiroshi Nagai, Chih Cheng Chang, Joseph R. Farah, Ben Prather, Laura Vertatschitsch, Britton Jeter, Kuo Chang Han, Shoko Koyama, William Snow, Lindy Blackburn, Erik M. Leitch, Rurik A. Primiani, Pierre Christian, Kyle D. Massingill, Shiro Ikeda, Remo P. J. Tilanus, S. A. Dzib, Charles F. Gammie, Ziyan Zhu, Ralph G. Marson, Aleksandar Popstefanija, Helge Rottmann, Chris Eckert, Lupin C.C. Lin, Michael H. Hecht, Silke Britzen, J. Anton Zensus, Christian M. Fromm, Sera Markoff, Wu Jiang, Cornelia Müller, A. Nadolski, David H. Hughes, Zhiyuan Li, Ue-Li Pen, Yosuke Mizuno, Sascha Trippe, Jinchi Hao, Gertie Geertsema, Garrett K. Keating, Lei Huang, Chi H. Nguyen, Koushik Chatterjee, Andrew Chael, Norbert Wex, Ronald Grosslein, Nimesh A. Patel, Aaron Faber, Rebecca Azulay, Stefan Heyminck, Kenji Toma, Do-Young Byun, Christopher Risacher, Wen Ping Lo, Geoffrey C. Bower, James M. Moran, Tyler Trent, Satoki Matsushita, Bart Ripperda, Dominique Broguiere, Antxon Alberdi, Kazi L.J. Rygl, Chet Ruszczyk, T. K. Sridharan, Antony A. Stark, Michael Bremer, James Hoge, M. Zeballos, Kamal Souccar, Paul T. P. Ho, Atish Kamble, Ciriaco Goddi, Feng Gao, Yau De Huang, Dan Bintley, Alan E. E. Rogers, Ryan Chilson, Jorge A. Preciado-López, A. Montaña, Hector Olivares, Mark Derome, Michael Janssen, Robert Freund, Thomas Bronzwaer, Jun Yi Koay, Kevin A. Dudevoir, Roberto Neri, Buell T. Jannuzi, Sandra Bustamente, Mislav Baloković, S. Navarro, Shami Chatterjee, Tod R. Lauer, Alejandro F. Sáez-Madain, Sjoerd T. Timmer, Chih Chiang Han, John E. Carlstrom, Luis C. Ho, Hugo Messias, Feryal Özel, Shuichiro Tsuda, Ryan Berthold, Taehyun Jung, Akihiko Hirota, Richard Lacasse, D. A. Graham, Vincent Piétu, Homin Jiang, Shan Shan Zhao, Lia Medeiros, Song Chu Chang, Jae-Young Kim, Hideo Ogawa, Sara Issaoun, Kotaro Moriyama, Stephen Padin, Roman Gold, N. W. Halverson, Venkatessh Ramakrishnan, C. Y. Kuo, Benjamin R. Ryan, Jason Dexter, Paul Shaw, Alan R. Whitney, Karl M. Menten, Aristeidis Noutsos, Kimihiro Kimura, Mark Kettenis, Ming-Tang Chen, Jonathan Weintroub, Neal R. Erickson, Chen Yu Yu, David R. Smith, André Young, Luciano Rezzolla, Jongsoo Kim, M. Poirier, Robert Wharton, Daniel C. M. Palumbo, Pierre Martin-Cocher, Hiroki Okino, Yutaka Hasegawa, Kuan Yu Liu, David P. Woody, Sven Dornbusch, George Reiland, Arash Roshanineshat, Pablo Torne, Daniel Michalik, John Wardle, David M. Gale, Ta Shun Wei, Uwe Bach, Ilse van Bemmel, Izumi Mizuno, Vincent L. Fish, Antonio Hernández-Gómez, Matthew R. Dexter, Paul Tiede, Rodrigo Amestica, Pim Schellart, Michael D. Johnson, Mel Rose, Callie Matulonis, J. G. A. Wouterloot, Jason SooHoo, Tomohisa Kawashima, T. M. Crawford, Dirk Muders, Craig Walther, Richard L. Plambeck, William Stahm, George Nystrom, David C. Forbes, Lynn D. Matthews, Avery E. Broderick, Ziri Younsi, Tuomas Savolainen, Neil M. Nagar, Alexander Allardi, M. Mora-Klein, Fumie Tazaki, Michael Lindqvist, Per Friberg, Olivier Gentaz, David J. James, Alan P. Marscher, Sang-Sung Lee, Chih-Wei Locutus Huang, Lijing Shao, Christiaan D. Brinkerink, Jason W. Henning, R. Laing, Feng Yuan, Junhan Kim, J. Peñalver, Michael Titus, Freek Roelofs, Laurent Loinard, Rubén Herrero-Illana, Gopal Narayanan, Alexander W. Raymond, Gregory Desvignes, Anne Kathrin Baczko, Ru-Sen Lu, Philippe Raffin, Jirong Mao, Colin J. Lonsdale, Jessica Dempsey, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Event Horizon Telescope, Astronomy, Anne Lähteenmäki Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Academy of Finland, European Commission, Alexander von Humboldt Foundation, John Templeton Foundation, China Scholarship Council, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), European Research Council, Generalitat Valenciana, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gordon and Betty Moore Foundation, Istituto Nazionale di Fisica Nucleare, Japanese Government, Japan Society for the Promotion of Science, Chinese Academy of Sciences, Max Planck Society, Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Science Foundation (US), National Natural Science Foundation of China, Natural Sciences and Engineering Research Council of Canada, National Research Foundation of Korea, Netherlands Organization for Scientific Research, National Research Foundation (South Africa), Russian Science Foundation, Ministero dell'Istruzione, dell'Università e della Ricerca, Alberdi, Antxón [0000-0002-9371-1033], Gómez Fernández, J. L. [0000-0003-4190-7613], Event Horizon Telescope Collaboration, T., Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A. -K., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D. -Y., Carlstrom, J. E., Chael, A., Chan, C. -K., Chatterjee, S., Chatterjee, K., Chen, M. -T., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. -W. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J. -Y., Kim, J., Kino, M., Koay, J. Y., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C. -Y., Lauer, T. R., Lee, S. -S., Li, Y. -R., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R. -S., Macdonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Muller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. C. M., Patel, N., Pen, U. -L., Pesce, D. W., Pietu, V., Plambeck, R., Popstefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. L. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F. P., Schuster, K. -F., Shao, L., Shen, Z., Small, D., Sohn, B. W., Soohoo, J., Tazaki, F., Tiede, P., Tilanus, R. P. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., Van Bemmel, I., Van Langevelde, H. J., Van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, A., Young, K., Younsi, Z., Yuan, F., Yuan, Y. -F., Zensus, J. A., Zhao, G., Zhao, S. -S., Zhu, Z., Algaba, J. -C., Allardi, A., Amestica, R., Bach, U., Beaudoin, C., Benson, B. A., Berthold, R., Blanchard, J. M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Dominguez, E., Chang, C. -C., Chang, S. -H., Chang, S. -C., Chen, C. -C., Chilson, R., Chuter, T. C., Rosado, R. C., Coulson, I. M., Crawford, T. M., Crowley, J., David, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K. A., Dzib, S. A., Eckert, C., Erickson, N. R., Everett, W. B., Faber, A., Farah, J. R., Fath, V., Folkers, T. W., Forbes, D. C., Freund, R., Gomez-Ruiz, A. I., Gale, D. M., Gao, F., Geertsema, G., Graham, D. A., Greer, C. H., Grosslein, R., Gueth, F., Halverson, N. W., Han, C. -C., Han, K. -C., Hao, J., Hasegawa, Y., Henning, J. W., Hernandez-Gomez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y. -D., Impellizzeri, C. M. V., Jiang, H., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R. A., Leitch, E. M., Li, C. -T., Lin, L. C. -C., Liu, C. -T., Liu, K. -Y., Lu, L. -M., Marson, R. G., Martin-Cocher, P. L., Massingill, K. D., Matulonis, C., Mccoll, M. P., Mcwhirter, S. R., Messias, H., Meyer-Zhao, Z., Michalik, D., Montana, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Nguyen, C. H., Nishioka, H., Norton, T., Nystrom, G., Ogawa, H., Oshiro, P., Padin, S., Parsons, H., Paine, S. N., Penalver, J., Phillips, N. M., Poirier, M., Pradel, N., Primiani, R. A., Raffin, P. A., Rahlin, A. S., Reiland, G., Risacher, C., Ruiz, I., Saez-Madain, A. F., Sassella, R., Schellart, P., Shaw, P., Silva, K. M., Shiokawa, H., Smith, D. R., Snow, W., Souccar, K., Sousa, D., Sridharan, T. K., Srinivasan, R., Stahm, W., Stark, A. A., Story, K., Timmer, S. T., Vertatschitsch, L., Walther, C., Wei, T. -S., Whitehorn, N., Whitney, A. R., Woody, D. P., Wouterloot, J. G. A., Wright, M., Yamaguchi, P., Yu, C. -Y., Zeballos, M., Ziurys, L., Alberdi, Antxón, Gómez Fernández, J. L., High Energy Astrophys. & Astropart. Phys (API, FNWI), and Gravitation and Astroparticle Physics Amsterdam

Subjects
010504 meteorology & atmospheric sciences, individual (M87) [galaxies], Event horizon, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, interferometers [instrumentation], black hole physics, FOS: Physical sciences, galaxies: individual, General Relativity and Quantum Cosmology (gr-qc), galaxies: individual: M87, 01 natural sciences, General Relativity and Quantum Cosmology, galaxies: individual (M87), instrumentation: interferometer, 0103 physical sciences, Very-long-baseline interferometry, Angular resolution, Instrumentation (computer programming), instrumentation: interferometers, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, high angular resolution [echniques], Event Horizon Telescope, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Supermassive black hole, Galaxy: center, high angular resolution [techniques], techniques: high angular resolution, gravitational lensing: strong, Astronomy and Astrophysics, center [Galaxy], Hydrogen maser, black hole physic, Astrophysics - Astrophysics of Galaxies, echniques: high angular resolution, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), strong [gravitational lensing], Millimeter, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ~1.3 mm, EHT angular resolution (λ/D) is ~25 μas, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of the EHT, detail the technology and instrumentation that enable observations, and provide measures of its performance. Meeting the EHT science objectives has required several key developments that have facilitated the robust extension of the VLBI technique to EHT observing wavelengths and the production of instrumentation that can be deployed on a heterogeneous array of existing telescopes and facilities. To meet sensitivity requirements, high-bandwidth digital systems were developed that process data at rates of 64 gigabit s−1, exceeding those of currently operating cm-wavelength VLBI arrays by more than an order of magnitude. Associated improvements include the development of phasing systems at array facilities, new receiver installation at several sites, and the deployment of hydrogen maser frequency standards to ensure coherent data capture across the array. These efforts led to the coordination and execution of the first Global EHT observations in 2017 April, and to event-horizon-scale imaging of the supermassive black hole candidate in M87.© 2019. The American Astronomical Society, The authors of this Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General de Asuntos del Personal Académico-Universidad Nacional 9 The Astrophysical Journal Letters, 875:L1 (17pp), 2019 April 10 The EHT Collaboration et al. Autónoma de México (DGAPA-UNAM, project IN112417); the European Research Council (ERC) Synergy Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); JSPS Overseas Research Fellowships; the Key Research Program of Frontier Sciences, Chinese, Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107- 2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST0705062, AST-0905844, AST-0922984, AST-1126433, AST1140030, DGE-1144085, AST-1207704, AST-1207730, AST1207752, MRI-1228509, OPP-1248097, AST-1310896, AST1312651, AST-1337663, AST-1440254, AST-1555365, AST1715061, AST-1615796, AST-1614868, AST-1716327, OISE1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11873028, 11873073, U1531245, 11473010); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (grant 2015-R1D1A1A01056807, the Global PhD Fellowship Grant: NRF-2015H1A2A1033752, and the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize (SPI 78-409); the New Scientific Frontiers with Precision, Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648); the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economía y Competitividad (grants AYA2015-63939-C2-1-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell’Istruzione Università e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Unionʼs Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; Chandra TM6-17006X

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2019
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