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1. The SARAO MeerKAT 1.3 GHz Galactic Plane Survey

Author

Goedhart, S., Cotton, W. D., Camilo, F., Thompson, M. A., Umana, G., Bietenholz, M., Woudt, P. A., Anderson, L. D., Bordiu, C., Buckley, D. A. H., Buemi, C. S., Bufano, F., Cavallaro, F., Chen, H., Chibueze, J. O., Egbo, D., Frank, B. S., Hoare, M. G., Ingallinera, A., Irabor, T., Kraan-Korteweg, R. C., Kurapati, S., Leto, P., Loru, S., Mutale, M., Obonyo, W. O., Plavin, A., Rajohnson, S. H. A., Rigby, A., Riggi, S., Seidu, M., Serra, P., Smart, B. M., Stappers, B. W., Steyn, N., Surnis, M., Trigilio, C., Williams, G. M., Abbott, T. D., Adam, R. M., Asad, K. M. B., Baloyi, T., Bauermeister, E. F., Bennet, T. G. H., Bester, H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., Cloete, K., de Villiers, M. S., de Villiers, D. I. L., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., Fourie, D. J., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, L. M. G., Hugo, B. V., Isaacson, A. I., Józsa, G. I. G., Jonas, J. L., Jordaan, J. D. B. L., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Lord, R. T., Macfarlane, P. S., Magnus, L. G., Magozore, C., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Maruping, P., McAlpine, K., Merry, B. C., Mgodeli, M., Millenaar, R. P., Mokone, O. J., Monama, T. E., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Nicolson, G. D., Ockards, M. T., Oozeer, N., Passmoor, S. S., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ratcliffe, S. M., Renil, R., Richter, L. L., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O. M., Tiplady, A. J., van Balla, T. J., van der Byl, A., Van Tonder, V., Venter, A. J., Venter, M., Welz, M. G., and Williams, L. P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251\deg $\le l \le$ 358\deg and 2\deg $\le l \le$ 61\deg at $|b| \le 1.5\deg $). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of $\sim$10--20 $\mu$ Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance., Comment: Accepted for publication in MNRAS. The data release is live and links can be found in the Data Availability Statement in the paper

Published
2023

2. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

Heywood, I., Rammala, I., Camilo, F., Cotton, W. D., Yusef-Zadeh, F., Abbott, T. D., Adam, R. M., Adams, G., Aldera, M. A., Asad, K. M. B., Bauermeister, E. F., Bennett, T. G. H., Bester, H. L., Bode, W. A., Botha, D. H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., de Villiers, D. I. L., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., February, S., Fourie, D. J., Frank, B. S., Gamatham, R. R. G., Geyer, M., Goedhart, S., Gouws, M., Gumede, S. C., Hlakola, M. J., Hokwana, A., Hoosen, S. W., Horrell, J. M. G., Hugo, B., Isaacson, A. I., Józsa, G. I. G., Jonas, J. L., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kenyon, J. S., Kotzé, P. P. A., Kriek, N., Kriel, H., Krishnan, V. K., Lehmensiek, R., Liebenberg, D., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Mahgoub, O., Makhaba, A., Makhathini, S., Malan, J. A., Manley, J. R., Marais, S. J., Martens, A., Mauch, T., Merry, B. C., Millenaar, R. P., Mnyandu, N., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T., Oozeer, N., Otto, A. J., Passmoor, S. S., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ramanujam, N. M. R., Ramudzuli, Z. R., Ratcliffe, S. M., Robyntjies, A., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M., Smirnov, O. M., Sofeya, L., Taljaard, B., Tasse, C., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., Van Tonder, V., Van Wyk, R., Venter, A. J., Venter, M., Wallace, B. H., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The inner $\sim$200 pc region of the Galaxy contains a 4 million M$_{\odot}$ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total intensity and spectral index mosaics of the region from 20 pointings (144 hours on-target in total), covering 6.5 square degrees with an angular resolution of 4$"$,at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT's high sensitivity, exceptional $u,v$-plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new non-thermal filament complexes, and enhanced views of the Radio Arc Bubble, Sgr A and Sgr B regions. This project is a SARAO public legacy survey, and the image products are made available with this article., Comment: 29 pages, 15 figures, 3 tables, accepted for publication in the The Astrophysical Journal. Replacement arXiv version with higher quality figures

Published
2022
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4. The MeerKAT Galaxy Cluster Legacy Survey I. Survey Overview and Highlights

Author

Knowles, K., Cotton, W. D., Rudnick, L., Camilo, F., Goedhart, S., Deane, R., Ramatsoku, M., Bietenholz, M. F., Brüggen, M., Button, C., Chen, H., Chibueze, J. O., Clarke, T. E., de Gasperin, F., Ianjamasimanana, R., Józsa, G. I. G., Hilton, M., Kesebonye, K. C., Kolokythas, K., Kraan-Korteweg, R. C., Lawrie, G., Lochner, M., Loubser, S. I., Marchegiani, P., Mhlahlo, N., Moodley, K., Murphy, E., Namumba, B., Oozeer, N., Parekh, V., Pillay, D. S., Passmoor, S. S., Ramaila, A. J. T., Ranchod, S., Retana-Montenegro, E., Sebokolodi, L., Sikhosana, S. P., Smirnov, O., Thorat, K., Venturi, T., Abbott, T. D., Adam, R. M., Adams, G., Aldera, M. A., Bauermeister, E. F., Bennett, T. G. H., Bode, W. A., Botha, D. H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., de Villiers, D. I. L., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., Foley, A. R., Fourie, D. J., Frank, B. S., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hlakola, M. J., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, J. M. G., Hugo, B. V., Isaacson, A. R., Jonas, J. L., Jordaan, J. D. B., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kotze, A. G., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Liebenberg, D., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Makhaba, A., Makhathini, S., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Mauch, T., McAlpine, K., Merry, B. C., Millenaar, R. P., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramanujam, N. M., Ramudzuli, Z. R., Ratcliffe, S. M., Renil, R., Robyntjies, A., Rust, A. N., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M., Sofeya, L., Taljaard, B., Tasse, C., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., van Dyk, C. L., Van Tonder, V., Van Wyk, R., Venter, A. J., Venter, M., Welz, M. G., Williams, L. P., and Xaia, B.

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

MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The MeerKAT Galaxy Cluster Legacy Survey (MGCLS) is a programme of long-track MeerKAT L-band (900-1670 MHz) observations of 115 galaxy clusters, observed for $\sim$6-10 hours each in full polarisation. The first legacy product data release (DR1), made available with this paper, includes the MeerKAT visibilities, basic image cubes at $\sim$8" resolution, and enhanced spectral and polarisation image cubes at $\sim$8" and 15" resolutions. Typical sensitivities for the full-resolution MGCLS image products are $\sim$3-5 {\mu}Jy/beam. The basic cubes are full-field and span 4 deg^2. The enhanced products consist of the inner 1.44 deg^2 field of view, corrected for the primary beam. The survey is fully sensitive to structures up to $\sim$10' scales and the wide bandwidth allows spectral and Faraday rotation mapping. HI mapping at 209 kHz resolution can be done at $0

Published
2021
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5. The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime

Author

Bailes, M., Jameson, A., Abbate, F., Barr, E. D., Bhat, N. D. R., Bondonneau, L., Burgay, M., Buchner, S. J., Camilo, F., Champion, D. J., Cognard, I., Demorest, P. B., Freire, P. C. C., Gautam, T., Geyer, M., Griessmeier, J. M., Guillemot, L., Hu, H., Jankowski, F., Johnston, S., Karastergiou, A., Karuppusamy, R., Kaur, D., Keith, M. J., Kramer, M., van Leeuwen, J., Lower, M. E., Maan, Y., McLaughlin, M. A., Meyers, B. W., Osłowski, S., Oswald, L. S., Parthasarathy, A., Pennucci, T., Posselt, B., Possenti, A., Ransom, S. M., Reardon, D. J., Ridolfi, A., Schollar, C. T. G., Serylak, M., Shaifullah, G., Shamohammadi, M., Shannon, R. M., Sobey, C., Song, X., Spiewak, R., Stairs, I. H., Stappers, B. W., van Straten, W., Szary, A., Theureau, G., Krishnan, V. Venkatraman, Weltevrede, P., Wex, N., Abbott, T. D., Adams, G. B., Burger, J. P., Gamatham, R. R. G., Gouws, M., Horn, D. M., Hugo, B., Joubert, A. F., Manley, J. R., McAlpine, K., Passmoor, S. S., Peens-Hough, A., Ramudzuli, Z. R., Rust, A., Salie, S., Schwardt, L. C., Siebrits, R., Van Tonder, G., Van Tonder, V., and Welz, M. G.

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

We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly-commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain (~2.8 K/Jy) low-system temperature (~18 K at 20cm) radio array that currently operates from 580-1670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar J0737-3039A, pulse profiles from 34 millisecond pulsars from a single 2.5h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR J0540-6919, and nulling identified in the slow pulsar PSR J0633-2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright millisecond pulsars confirm that MeerKAT delivers exceptional timing. PSR J2241-5236 exhibits a jitter limit of <4 ns per hour whilst timing of PSR J1909-3744 over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1000 pulsars per day and the future deployment of S-band (1750-3500 MHz) receivers will further enhance its capabilities., Comment: 20 pages, 16 Figures, 4 Tables, accepted for publication in PASA

Published
2020
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6. The 1.28 GHz MeerKAT DEEP2 Image

Author

Mauch, T., Cotton, W. D., Condon, J. J., Matthews, A. M., Abbott, T. D., Adam, R. M., Aldera, M. A., Asad, K. M. B., Bauermeister, E. F., Bennett, T. G. H., Bester, H., Botha, D. H., Brederode, L. R. S., Brits, Z. B., Buchner, S. J., Burger, J. P., Camilo, F., Chalmers, J. M., Cheetham, T., de Villiers, D., de Villiers, M. S., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., February, S., Frank, B. S., Gamatham, R. R. G., Geyer, M., Goedhart, S., Gounden, S., Gumede, S. C., Heywood, I., Hlakola, M. J., Horrell, J. M. G., Hugo, B., Isaacson, A. R., Józsa, G. I. G., Jonas, J. L., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kriek, N., Kriel, H., Kusel, T. W., Lehmensiek, R., Loots, A., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Martens, A., Merry, B., Millenaar, R., Mnyandu, N., Moeng, I. P. T., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T. O., Oozeer, N., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ramudzuli, Z. R., Renil, R., Richter, L. L., Robyntjies, A., Salie, S., Schollar, C. T. G., Schwardt, L. C., Serylak, M., Siebrits, R., Sirothia, S. K., Smirnov, O. M., Sofeya, L., Stone, G., Taljaard, B., Tasse, C., Theron, I. P., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., Van Tonder, V., Wallace, B. H., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one $\approx 68'$ FWHM primary beam area with $7.6''$ FWHM resolution and $0.55 \pm 0.01$ $\mu$Jy/beam rms noise. Its J2000 center position $\alpha=04^h 13^m 26.4^s$, $\delta=-80^\circ 00' 00''$ was selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary beam attenuation pattern, estimate telescope pointing errors, and pinpoint $(u,v)$ coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion $P(D)$ distribution from $0.25$ to $10$ $\mu$Jy with counts of individual DEEP2 sources between $10$ $\mu$Jy and $2.5$ mJy. Most sources fainter than $S \sim 100$ $\mu$Jy are distant star-forming galaxies obeying the FIR/radio correlation, and sources stronger than $0.25$ $\mu$Jy account for $\sim93\%$ of the radio background produced by star-forming galaxies. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson (2014) model for the evolution of star-forming galaxies based on UV and infrared data underpredicts our 1.4 GHz source count in the range $-5 \lesssim \log[S(\mathrm{Jy})] \lesssim -4$., Comment: 20 pages, 18 figures. Accepted for publication in ApJ

Published
2019
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7. Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Author

Heywood, I., Camilo, F., Cotton, W. D., Yusef-Zadeh, F., Abbott, T. D., Adam, R. M., Aldera, M. A., Bauermeister, E. F., Booth, R. S., Botha, A. G., Botha, D. H., Brederode, L. R. S., Brits, Z. B., Buchner, S. J., Burger, J. P., Chalmers, J. M., Cheetham, T., de Villiers, D., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., Foley, A. R., Fourie, D. J., Gamatham, R. R. G., Goedhart, S., Gounden, S., Hlakola, M. J., Hoek, C. J., Hokwana, A., Horn, D. M., Horrell, J. M. G., Hugo, B., Isaacson, A. R., Jonas, J. L., Jordaan, J. D. B. L., Joubert, A. F., Józsa, G. I. G., Julie, R. P. M., Kapp, F. B., Kenyon, J. S., Kotzé, P. P. A., Kriel, H., Kusel, T. W., Lehmensiek, R., Liebenberg, D., Loots, A., Lord, R. T., Lunsky, B. M., Macfarlane, P. S., Magnus, L. G., Magozore, C. M., Mahgoub, O., Main, J. P. L., Malan, J. A., Malgas, R. D., Manley, J. R., Maree, M. D. J., Merry, B., Millenaar, R., Mnyandu, N., Moeng, I. P. T., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Oozeer, N., Otto, A. J., Passmoor, S. S., Pate, A. A., Peens-Hough, A., Perkins, S. J., Ratcliffe, S. M., Renil, R., Rust, A., Salie, S., Schwardt, L. C., Serylak, M., Siebrits, R., Sirothia, S. K., Smirnov, O. M., Sofeya, L., Swart, P. S., Tasse, C., Taylor, D. T., Theron, I. P., Thorat, K., Tiplad, A. J., Tshongweni, S., van Balla, T. J., van der Byl, A., van der Merwe, C., van Dyk, C. L., Van Rooyen, R., Van Tonder, V., Van Wyk, R., Wallace, B. H., Welz, M. G., and Williams, L. P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The Galactic Centre contains a supermassive black hole with a mass of 4 million suns within an environment that differs markedly from that of the Galactic disk. While the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings. Also, while the levels of star formation in the Galactic Centre have been approximately constant over the last few hundred Myr, there is evidence of elevated short-duration bursts, strongly influenced by interaction of the black hole with the enhanced gas density present within the ring-like Central Molecular Zone at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200 pc region is characterized by large amounts of warm molecular gas, a high cosmic ray ionization rate, unusual gas chemistry, enhanced synchrotron emission, and a multitude of radio-emitting magnetised filaments, the origin of which has not been established. Here we report radio imaging that reveals bipolar bubbles spanning 1 degree x 3 degrees (140 parsecs x 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 x 10^52 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities., Comment: 25 pages, 3 figures, 3 tables, authors' version of a Letter published in Nature on 11 September 2019

Published
2019
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8. Upgrade of the mechanically pumped CO[formula omitted] two-phase cooling system for the alpha magnetic spectrometer on the international space station

Author

Ambrosi, G., Bertucci, B., Bollweg, K., Burger, J., Cai, X., Capell, M., Chung, C.H., Chuang, Y.R., Clark, C., Ding, T., FanChiang, Y.J., Gargiulo, C., Gaggiotti, M., Guo, L., He, Z.H., Heil, M., Heilig, J., Karpinski, W., Koutsenko, V., Kulemzin, A., Lübelsmeyer, K., Martin, T., Mo, D.C., Morelli, G., Miao, J.Y., Mott, P., Mussolin, L., Schael, S., von Dratzig, A. Schutlz, Schwering, G., Scolieri, G., Siedenburg, T., Solano, C., Urban, T., Verlaat, B., Wang, S.H., Wlochal, M., Yan, J.J., Yang, Y., Yu, Y.M., Zeng, R.C., and Zhang, Z.

Published
2023
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9. Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

Camilo, F., Scholz, P., Serylak, M., Buchner, S., Merryfield, M., Kaspi, V. M., Archibald, R. F., Bailes, M., Jameson, A., van Straten, W., Sarkissian, J., Reynolds, J. E., Johnston, S., Hobbs, G., Abbott, T. D., Adam, R. M., Adams, G. B., Alberts, T., Andreas, R., Asad, K. M. B., Baker, D. E., Baloyi, T., Bauermeister, E. F., Baxana, T., Bennett, T. G. H., Bernardi, G., Booisen, D., Booth, R. S., Botha, D. H., Boyana, L., Brederode, L. R. S., Burger, J. P., Cheetham, T., Conradie, J., Conradie, J. P., Davidson, D. B., de Bruin, G., de Swardt, B., de Villiers, C., de Villiers, D. I. L., de Villiers, M. S., de Villiers, W., de Waal, C., Dikgale, M. A., Toit, G. du, Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B., Fataar, S., Foley, A. R., Foster, G., Fourie, D., Gamatham, R., Gatsi, T., Geschke, R., Goedhart, S., Grobler, T. L., Gumede, S. C., Hlakola, M. J., Hokwana, A., Hoorn, D. H., Horn, D., Horrell, J., Hugo, B., Isaacson, A., Jacobs, O., van Rensburg, J. P. Jansen, Jonas, J. L., Jordaan, B., Joubert, A., Joubert, F., Jozsa, G. I. G., Julie, R., Julius, C. C., Kapp, F., Karastergiou, A., Karels, F., Kariseb, M., Karuppusamy, R., Kasper, V., Knox-Davies, E. C., Koch, D., Kotze, P. P. A., Krebs, A., Kriek, N., Kriel, H., Kusel, T., Lamoor, S., Lehmensiek, R., Liebenberg, D., Liebenberg, I., Lord, R. T., Lunsky, B., Mabombo, N., Macdonald, T., Macfarlane, P., Madisa, K., Mafhungo, L., Magnus, L. G., Magozore, C., Mahgoub, O., Main, J. P. L., Makhathini, S., Malan, J. A., Malgas, P., Manley, J. R., Manzini, M., Marais, L., Marais, N., Marais, S. J., Maree, M., Martens, A., Matshawule, S. D., Matthysen, N., Mauch, T., Nally, L. D. Mc, Merry, B., Millenaar, R. P., Mjikelo, C., Mkhabela, N., Mnyandu, N., Moeng, I. T., Mokone, O. J., Monama, T. E., Montshiwa, K., Moss, V., Mphego, M., New, W., Ngcebetsha, B., Ngoasheng, K., Niehaus, H., Ntuli, P., Nzama, A., Obies, F., Obrocka, M., Ockards, M. T., Olyn, C., Oozeer, N., Otto, A. J., Padayachee, Y., Passmoor, S., Patel, A. A., Paula, S., Peens-Hough, A., Pholoholo, B., Prozesky, P., Rakoma, S., Ramaila, A. J. T., Rammala, I., Ramudzuli, Z. R., Rasivhaga, M., Ratcliffe, S., Reader, H. C., Renil, R., Richter, L., Robyntjies, A., Rosekrans, D., Rust, A., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L., Seranyane, S., Sethosa, G., Sharpe, C., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O., Smith, S., Sofeya, L., Songqumase, N., Spann, R., Stappers, B., Steyn, D., Steyn, T. J., Strong, R., Struthers, A., Stuart, C., Sunnylall, P., Swart, P. S., Taljaard, B., Tasse, C., Taylor, G., Theron, I. P., Thondikulam, V., Thorat, K., Tiplady, A., Toruvanda, O., van Aardt, J., van Balla, T., Heever, L. van den, van der Byl, A., van der Merwe, C., van der Merwe, P., van Niekerk, P. C., van Rooyen, R., van Staden, J. P., van Tonder, V., van Wyk, R., Wait, I., Walker, A. L., Wallace, B., Welz, M., Williams, L. P., Xaia, B., Young, N., and Zitha, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation., Comment: Published in ApJ (2018 April 5); 13 pages, 4 figures

Published
2018
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10. The speed limit of optoelectronics

Author

Ossiander, M., Golyari, K., Scharl, K., Lehnert, L., Siegrist, F., Bürger, J. P., Zimin, D., Gessner, J. A., Weidman, M., Floss, I., Smejkal, V., Donsa, S., Lemell, C., Libisch, F., Karpowicz, N., Burgdörfer, J., Krausz, F., and Schultze, M.

Published
2022
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11. The Alpha Magnetic Spectrometer (AMS) on the international space station: Part II — Results from the first seven years

Author

Aguilar, M., Ali Cavasonza, L., Ambrosi, G., Arruda, L., Attig, N., Barao, F., Barrin, L., Bartoloni, A., Başeğmez-du Pree, S., Bates, J., Battiston, R., Behlmann, M., Beischer, B., Berdugo, J., Bertucci, B., Bindi, V., de Boer, W., Bollweg, K., Borgia, B., Boschini, M.J., Bourquin, M., Bueno, E.F., Burger, J., Burger, W.J., Burmeister, S., Cai, X.D., Capell, M., Casaus, J., Castellini, G., Cervelli, F., Chang, Y.H., Chen, G.M., Chen, H.S., Chen, Y., Cheng, L., Chou, H.Y., Chouridou, S., Choutko, V., Chung, C.H., Clark, C., Coignet, G., Consolandi, C., Contin, A., Corti, C., Cui, Z., Dadzie, K., Dai, Y.M., Delgado, C., Della Torre, S., Demirköz, M.B., Derome, L., Di Falco, S., Di Felice, V., Díaz, C., Dimiccoli, F., von Doetinchem, P., Dong, F., Donnini, F., Duranti, M., Egorov, A., Eline, A., Feng, J., Fiandrini, E., Fisher, P., Formato, V., Freeman, C., Galaktionov, Y., Gámez, C., García-López, R.J., Gargiulo, C., Gast, H., Gebauer, I., Gervasi, M., Giovacchini, F., Gómez-Coral, D.M., Gong, J., Goy, C., Grabski, V., Grandi, D., Graziani, M., Guo, K.H., Haino, S., Han, K.C., Hashmani, R.K., He, Z.H., Heber, B., Hsieh, T.H., Hu, J.Y., Huang, Z.C., Hungerford, W., Incagli, M., Jang, W.Y., Jia, Yi, Jinchi, H., Kanishev, K., Khiali, B., Kim, G.N., Kirn, Th., Konyushikhin, M., Kounina, O., Kounine, A., Koutsenko, V., Kuhlman, A., Kulemzin, A., La Vacca, G., Laudi, E., Laurenti, G., Lazzizzera, I., Lebedev, A., Lee, H.T., Lee, S.C., Leluc, C., Li, J.Q., Li, M., Li, Q., Li, S., Li, T.X., Li, Z.H., Light, C., Lin, C.H., Lippert, T., Liu, Z., Lu, S.Q., Lu, Y.S., Luebelsmeyer, K., Luo, J.Z., Lyu, S.S., Machate, F., Mañá, C., Marín, J., Marquardt, J., Martin, T., Martínez, G., Masi, N., Maurin, D., Menchaca-Rocha, A., Meng, Q., Mo, D.C., Molero, M., Mott, P., Mussolin, L., Ni, J.Q., Nikonov, N., Nozzoli, F., Oliva, A., Orcinha, M., Palermo, M., Palmonari, F., Paniccia, M., Pashnin, A., Pauluzzi, M., Pensotti, S., Phan, H.D., Plyaskin, V., Pohl, M., Porter, S., Qi, X.M., Qin, X., Qu, Z.Y., Quadrani, L., Rancoita, P.G., Rapin, D., Reina Conde, A., Rosier-Lees, S., Rozhkov, A., Rozza, D., Sagdeev, R., Schael, S., Schmidt, S.M., Schulz von Dratzig, A., Schwering, G., Seo, E.S., Shan, B.S., Shi, J.Y., Siedenburg, T., Solano, C., Song, J.W., Sonnabend, R., Sun, Q., Sun, Z.T., Tacconi, M., Tang, X.W., Tang, Z.C., Tian, J., Ting, Samuel C.C., Ting, S.M., Tomassetti, N., Torsti, J., Tüysüz, C., Urban, T., Usoskin, I., Vagelli, V., Vainio, R., Valente, E., Valtonen, E., Vázquez Acosta, M., Vecchi, M., Velasco, M., Vialle, J.P., Wang, L.Q., Wang, N.H., Wang, Q.L., Wang, S., Wang, X., Wang, Z.X., Wei, J., Weng, Z.L., Wu, H., Xiong, R.Q., Xu, W., Yan, Q., Yang, Y., Yi, H., Yu, Y.J., Yu, Z.Q., Zannoni, M., Zhang, C., Zhang, F., Zhang, F.Z., Zhang, J.H., Zhang, Z., Zhao, F., Zheng, Z.M., Zhuang, H.L., Zhukov, V., Zichichi, A., Zimmermann, N., and Zuccon, P.

Published
2021
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12. Varying water activity and momentum transfer on comet 67P/Churyumov-Gerasimenko from its non-gravitational forces and torques.

Author

Attree, N., Gutiérrez, P., Groussin, O., Bürger, J., Keller, H. U., Kramer, T., Lasagni Manghi, R., Läuter, M., Lemos, P., Markkanen, J., Marschall, R., and Schuckart, C.

Subjects
MOMENTUM transfer, CHURYUMOV-Gerasimenko comet, CELESTIAL mechanics, GEOMORPHOLOGICAL mapping, SOLAR radiation
Abstract

Aims. We investigate the ability of a simultaneous fitting of comet 67P/Churyumov-Gerasimenko's non-gravitational forces, torques, and total water-outgassing rate, as observed by Rosetta, to constrain complex thermophysical models of cometary material. Methods. We extend the previous work of fitting geographically defined surface outgassing models to the Rosetta observations by testing the effects of a more detailed geomorphological mapping, the resolution of the shape-model used, self-heating by neighbouring facets on the shape-model, thermal inertia in the outgassing solution, and the variation in the momentum coupling between the gas and the nucleus. We also directly compare the non-gravitational acceleration curves available in the literature. Results. We correct an error in the calculation of pole-orientation in the previous paper. We find that, under the assumptions of the model, non-gravitational forces and torques are driven by water sublimation from the nucleus, thermal inertia and self-heating have only minor effects, spatially uniform activity cannot explain 67P's non-gravitational dynamics, spatially uniform momentum transfer cannot explain 67P's non-gravitational dynamics, and different terrain types have different instantaneous responses to insolation. Conclusions. Consolidated terrain facing south on 67P/Churyumov-Gerasimenko has a high outgassing flux, a steep response to insolation, and a large gas momentum transfer coefficient. Instead, that facing north behaves differently, producing little to no water outgassing, and with a lower momentum transfer efficiency. Dusty terrain also has a lower outgassing rate and momentum transfer efficiency, and either depletes its volatile component or is buried in fall-back as the comet approaches the Sun. Momentum transfer appears correlated with insolation, likely due to an increased enhancement in the gas temperature as the dust it flows through is heated. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Cognitive Architecture for Direction of Attention Founded on Subliminal Memory Searches, Pseudorandom and Nonstop

Author

Burger, J. R.

Subjects
Computer Science - Artificial Intelligence, Computer Science - Neural and Evolutionary Computing, I.2.0, C.1.3
Abstract

By way of explaining how a brain works logically, human associative memory is modeled with logical and memory neurons, corresponding to standard digital circuits. The resulting cognitive architecture incorporates basic psychological elements such as short term and long term memory. Novel to the architecture are memory searches using cues chosen pseudorandomly from short term memory. Recalls alternated with sensory images, many tens per second, are analyzed subliminally as an ongoing process, to determine a direction of attention in short term memory., Comment: 6 pages, 4 figures

Published
2008

14. Performance of the AMS-02 Transition Radiation Detector

Author

Doetinchem, P. v., Fopp, S., Karpinski, W., Kirn, T., Luebelsmeyer, K., Orboeck, J., Schael, S., von Dratzig, A. Schultz, Schwering, G., Siedenburg, T., Siedling, R., Wallraff, W., Becker, U., Burger, J., Henning, R., Kounine, A., Koutsenko, V., and Wyatt, J.

Subjects
Astrophysics
Abstract

For cosmic particle spectroscopy on the International Space Station the AMS experiment will be equipped with a Transition Radiation Detector (TRD) to improve particle identification. The TRD has 20 layers of fleece radiator with Xe/CO2 proportional mode straw tube chambers. They are supported in a conically shaped octagon structure made of CFC-Al-honeycomb. For low power consumption VA analog multiplexers are used as front-end readout. A 20 layer prototype built from final design components has achieved proton rejections from 100 to 2000 at 90% electron efficiency for proton beam energies up to 250 GeV with cluster counting, likelihood and neural net selection algorithms., Comment: 11 pages, 25 figures, espcrc2.sty (elsevier 2-column)

Published
2006
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17. Data-stationary Architecture to Execute Quantum Algorithms Classically

Author

Burger, J. R.

Subjects
Computer Science - Hardware Architecture, C.1.2
Abstract

This paper presents a data stationary architecture in which each word has an attached address field. Address fields massively update in parallel to record data interchanges. Words do not move until memory is read for post processing. A sea of such cells can test large-scale quantum algorithms, although other programming is possible.

Published
2004

18. Symmetric and anti-symmetric quantum functions

Author

Burger, J. R.

Subjects
Computer Science - Other Computer Science, Quantum Physics, F.1.2
Abstract

This paper introduces and analyzes symmetric and anti-symmetric quantum binary functions. Generally, such functions uniquely convert a given computational basis state into a different basis state, but with either a plus or a minus sign. Such functions may serve along with a constant function (in a Deutsch-Jozsa type of algorithm) to provide 2**n deterministic qubit combinations (for n qubits) instead of just one., Comment: Rewrote for clarity; added references to reversible computing; removed mention of Simon's functions

Published
2003

23. Hyperspectral Imaging

Author

Gowen, A. A., Gaston, E., Burger, J., Barbosa-Cánovas, Gustavo V., Series editor, O'Donnell, Colm P., editor, Fagan, Colette, editor, and Cullen, P.J., editor

Published
2014
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24. A search for squarks of Rp-violating SUSY at HERA

Author

Aid, S, Andreev, V, Andrieu, B, Appuhn, RD, Arpagaus, M, Babaev, A, Bähr, J, Bán, J, Ban, Y, Baranov, P, Barrelet, E, Barschke, R, Bartel, W, Barth, M, Bassler, U, Beck, HP, Behrend, HJ, Belousov, A, Berger, Ch, Bernardi, G, Bernet, R, Bertrand-Coremans, G, Besançon, M, Beyer, R, Biddulph, P, Bispham, P, Bizot, JC, Blobel, V, Borras, K, Botterweck, F, Boudry, V, Braemer, A, Braunschweig, W, Brisson, V, Bruel, P, Bruncko, D, Brune, C, Buchholz, R, Büngener, L, Bürger, J, Büsser, FW, Buniatian, A, Burke, S, Burton, MJ, Buschhorn, G, Campbell, AJ, Carli, T, Charles, F, Charlet, M, Clarke, D, Clegg, AB, Clerbaux, B, Cocks, S, Contreras, JG, Cormack, C, Coughlan, JA, Courau, A, Cousinou, MC, Cozzika, G, Criegee, L, Cussans, DG, Cvach, J, Dagoret, S, Dainton, JB, Dau, WD, Daum, K, David, M, Davis, CL, Delcourt, B, De Roeck, A, De Wolf, EA, Dirkmann, M, Dixon, P, Di Nezza, P, Dlugosz, W, Dollfus, C, Dowell, JD, Dreis, HB, Droutskoi, A, Düllmann, D, Dünger, O, Duhm, H, Ebert, J, Ebert, TR, Eckerlin, G, Efremenko, V, Egli, S, Eichler, R, Eisele, F, Eisenhandler, E, Ellison, RJ, Elsen, E, Erdmann, M, Erdmann, W, Evrard, E, Fahr, AB, Favart, L, Fedotov, A, Feeken, D, and Felst, R

Subjects
Nuclear & Particles Physics
Published
1996

31. Open Repair

Author

Schumpelick, V., Klinge, U., Rosch, R., Conze, J., Junge, K., Stumpf, M., Prescher, A., Kingsnorth, A., Machairas, A., 3rd, Van Geffen, H. J. A. A., Kreb, D., Simmermacher, R. K. J., Olsman, J., Van der Werken, Ch., Binnebösel, M., Halm, J. A., Burger, J. W. A., van’t Riet, M., Lange, J. F., Jeekel, J., Schumpelick, Volker, editor, and Fitzgibbons, Robert J., editor

Published
2007
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41. The Protein Forge - Interactive Building of Polypeptides

Author

Bürger, J. and Bürger, J.

Abstract

Proteins carry out the algorithms of life. As such, they play an integral role in Systems biology. Given the rapid development of Systems biology, understanding biological processes at a molecular level has become more important to other disciplines, like medicine, as well. Yet, current didactic methods often fail to teach their students biochemistry effectively. We present the Protein Forge, a Virtual Reality application that aims to help primarily medical students to identify amino acids, the building blocks of proteins, and to teach them how those amino acids are chemically linked. The program follows a predefined workflow: its user identifies amino acids from a naturally occurring protein sequence one after the other. When choosing the right amino acid, the user is presented with an animation, showing the formation of a peptide bond, i.e., the bond between two amino acids. The program was implemented in scenery, an open-source framework for rendering VR scenes. To display amino acids, we developed a rudimentary molecular viewer for scenery, consisting of a data structure to store the molecule data and an algorithm to determine the atom positions in space for a given molecule. A video of the experience can be found here:https://cloudstore. zih.tu-dresden.de/index.php/s/JB898wJFgp2r6fT, the respective code here: https:// github.com/scenerygraphics/scenery/tree/peptide_chain.

Published
2022

42. trx-jvm - A library for reading TRX tractography files for the Java VM

Author

(0000-0002-1179-8228) Günther, U., Notaro, C., Bürger, J., (0000-0002-1179-8228) Günther, U., Notaro, C., and Bürger, J.

Abstract

trx-jvm is a library implementing TRX (say, tee-ar-ex) file reading for JVM-based languages. TRX is a novel, open-source format for storing tractography data. trx-jvm was written with performance in mind, and uses imglib2 CellImgs for large array storage and access. It is able to parse and load a 4 GiB TRX file with 500000 streamlines in about 18 seconds on a standard notebook.

Published
2022

44. trx-jvm - A library for reading TRX tractography files for the Java VM

Author

Günther, U., Notaro, C., and Bürger, J.

Subjects
Streamlines, Tractography, Visualization, Neuroscience
Abstract

trx-jvm is a library implementing TRX (say, tee-ar-ex) file reading for JVM-based languages. TRX is a novel, open-source format for storing tractography data. trx-jvm was written with performance in mind, and uses imglib2 CellImgs for large array storage and access. It is able to parse and load a 4 GiB TRX file with 500000 streamlines in about 18 seconds on a standard notebook.

Published
2022

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