Search

Your search keyword '"Y. Y Kovalev"' showing total 74 results
Start Over Author "Y. Y Kovalev"
74 results on '"Y. Y Kovalev"'

1. Searches for Neutrinos in the Direction of Radio-bright Blazars with the ANTARES Telescope

Author

A. Albert, S. Alves, M. André, M. Ardid, S. Ardid, J.-J. Aubert, J. Aublin, B. Baret, S. Basa, Y. Becherini, B. Belhorma, M. Bendahman, F. Benfenati, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, M. Bouta, M. C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, B. Caiffi, D. Calvo, S. Campion, A. Capone, L. Caramete, F. Carenini, J. Carr, V. Carretero, S. Celli, L. Cerisy, M. Chabab, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, J. A. B. Coelho, A. Coleiro, R. Coniglione, P. Coyle, A. Creusot, A. S. M. Cruz, A. F. Díaz, B. De Martino, C. Distefano, I. Di Palma, A. Domi, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, T. van Eeden, D. van Eijk, S. El Hedri, N. El Khayati, A. Enzenhöfer, P. Fermani, G. Ferrara, F. Filippini, L. Fusco, S. Gagliardini, J. García, C. Gatius Oliver, P. Gay, N. Geißelbrecht, H. Glotin, R. Gozzini, R. Gracia Ruiz, K. Graf, C. Guidi, L. Haegel, S. Hallmann, H. van Haren, A. J. Heijboer, Y. Hello, J. J. Hernández-Rey, J. Hößl, J. Hofestädt, F. Huang, G. Illuminati, C. W. James, B. Jisse-Jung, M. de Jong, P. de Jong, M. Kadler, O. Kalekin, U. Katz, A. Kouchner, Y. A Kovalev, Y. Y Kovalev, I. Kreykenbohm, V. Kulikovskiy, R. Lahmann, M. Lamoureux, A. Lazo, D. Lefèvre, E. Leonora, G. Levi, S. Le Stum, D. Lopez-Coto, S. Loucatos, L. Maderer, J. Manczak, M. Marcelin, A. Margiotta, A. Marinelli, J. A. Martínez-Mora, P. Migliozzi, A. Moussa, R. Muller, S. Navas, E. Nezri, B. Ó Fearraigh, E. Oukacha, A. Păun, G. E. Păvălaş, S. Peña-Martínez, M. Perrin-Terrin, V. Pestel, P. Piattelli, A. Plavin, C. Poirè, V. Popa, T. Pradier, A. Pushkarev, N. Randazzo, D. Real, S. Reck, G. Riccobene, A. Romanov, A. Sánchez-Losa, A. Saina, F. Salesa Greus, D. F. E. Samtleben, M. Sanguineti, P. Sapienza, J. Schnabel, J. Schumann, F. Schüssler, J. Seneca, M. Spurio, Th. Stolarczyk, M. Taiuti, Y. Tayalati, S. J. Tingay, S. Troitsky, B. Vallage, G. Vannoye, V. Van Elewyck, S. Viola, D. Vivolo, J. Wilms, S. Zavatarelli, A. Zegarelli, J. D. Zornoza, J. Zúñiga, ANTARES Collaboration, T. Hovatta, S. Kiehlmann, I. Liodakis, V. Pavlidou, A. C. S Readhead, and OVRO Collaboration

Subjects
Neutrino astronomy, Blazars, Astrophysics, QB460-466
Abstract

Active galaxies, especially blazars, are among the most promising extragalactic candidates for high-energy neutrino sources. To date, ANTARES searches included these objects and used GeV–TeV γ -ray flux to select blazars. Here, a statistically complete blazar sample selected by their bright radio emission is used as the target for searches of origins of neutrinos collected by the ANTARES neutrino telescope over 13 yr of operation. The hypothesis of a neutrino–blazar directional correlation is tested by pair counting and a complementary likelihood-based approach. The resulting posttrial p -value is 3.0% (2.2 σ in the two-sided convention). Additionally, a time-dependent analysis is performed to search for temporal clustering of neutrino candidates as a means of detecting neutrino flares in blazars. None of the investigated sources alone reaches a significant flare detection level. However, the presence of 18 sources with a pretrial significance above 3 σ indicates a p = 1.4% (2.5 σ in the two-sided convention) detection of a time-variable neutrino flux. An a posteriori investigation reveals an intriguing temporal coincidence of neutrino, radio, and γ -ray flares of the J0242+1101 blazar at a p = 0.5% (2.9 σ in the two-sided convention) level. Altogether, the results presented here suggest a possible connection of neutrino candidates detected by the ANTARES telescope with radio-bright blazars.

Published
2024
Full Text
View/download PDF

2. Polarimetric properties of Event Horizon Telescope targets from ALMA

Author

Goddi, Ciriaco, Marti-Vidal, Ivan, Messias, Hugo, Bower, Geoffrey C., Broderick, Avery E., Dexter, Jason, Marrone, Daniel P., Moscibrodzka, Monika, Nagai, Hiroshi, Algaba, Juan Carlos, Asada, Keiichi, Crew, Geoffrey B., Gomez, Jose L., Impellizzeri, C. M. Violette, Janssen, Michael, Kadler, Matthias, Krichbaum, Thomas P., Lico, Rocco, Matthews, Lynn D., Nathanail, Antonios, Ricarte, Angelo, Ros, Eduardo, Younsi, Ziri, Collaboration, The Event Horizon Telescope, Bruni, Gabriele, Gopakumar, A., Hernandez-Gomez, Antonio, Herrero-Illana, Ruben, Ingram, Adam, Komossa, S., Muders, Y. Y. Kovalev Dirk, Perucho, Manel, Rosch, Florian, and Valtonen, Mauri

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

We present the results from a full polarization study carried out with ALMA during the first VLBI campaign, which was conducted in Apr 2017 in the $\lambda$3mm and $\lambda$1.3mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud AGN. We detect high linear polarization fractions (2-15%) and large rotation measures (RM $>10^{3.3}-10^{5.5}$ rad m$^{-2}$). For Sgr A* we report a mean RM of $(-4.2\pm0.3) \times10^5$ rad m$^{-2}$ at 1.3 mm, consistent with measurements over the past decade, and, for the first time, an RM of $(-2.1\pm0.1) \times10^5$ rad m$^{-2}$ at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at mm wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year time-scale, spanning the range from -1.2 to 0.3 $\times\,10^5$ rad m$^{-2}$ at 3 mm and -4.1 to 1.5 $\times\,10^5$ rad m$^{-2}$ at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT and ALMA. These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA., Comment: 62 pages, 26 figures, published in The Astrophysical Journal Letters on March 24, 2021

Published
2021
Full Text
View/download PDF

3. Radioastron Discovery of A Mini-Cocoon Around the Restarted Parsec-Scale Jet in 3C 84

Author

T Savolainen, G Giovannini, Y Y Kovalev, M Perucho, J M Anderson, G Bruni, P G Edwards, A Fuentes, M Giroletti, J L.Gómez, K Hada, S-S Lee, M M Lisakov, A P Lobanov, J López-Miralles, M Orienti, L Petrov, A V Plavin, B W Sohn, K V Sokolovsky, Petr A Voitsik, and J A Zensus

Subjects
Astronomy, Astrophysics
Abstract

We present RadioAstron space-based very long baseline interferometry (VLBI) observations of the nearby radio galaxy 3C 84 (NGC 1275) at the centre of the Perseus cluster. The observations were carried out during a perigee passage of the Spektr-R spacecraft on September 21–22, 2013 and involved a global array of 24 ground radio telescopes observing at 5 GHz and 22 GHz, together with the Space Radio Telescope (SRT). Furthermore, the Very Long Baseline Array (VLBA) and the phased Very Large Array (VLA) observed the source quasi-simultaneously at 15 GHz and 43 GHz. Fringes between the ground array and the SRT were detected on baseline lengths up to 8.1 times the Earth’s diameter, providing unprecedented resolution for 3C 84 at these wavelengths. We note that the corresponding fringe spacing is 125 μas at 5 GHz and 27 μas at 22 GHz. Our space-VLBI images reveal a previously unseen sub-structure inside the compact ∼1 pc long jet that was ejected about ten years earlier. In the 5 GHz image, we detected, for the first time, low-intensity emission from a cocoon-like structure around the restarted jet. Our results suggest that the increased power of the young jet is inflating a bubble of hot plasma as it carves its way through the ambient medium of the central region of the galaxy. Here, we estimate the minimum energy stored in the mini-cocoon, along with its pressure, volume, expansion speed, and the ratio of heavy particles to relativistic electrons, as well as the density of the ambient medium. About half of the energy delivered by the jet is dumped into the mini-cocoon and the quasi-spherical shape of the bubble suggests that this energy may be transferred to a significantly larger volume of the interstellar medium than what would be accomplished by the well-collimated jet on its own. The pressure of the hot mini-cocoon also provides a natural explanation for the almost cylindrical jet profile seen in the 22 GHz RadioAstron image.

Published
2023
Full Text
View/download PDF

4. VLBI observations of helical jets: hints on the nature of radio-jets

Author

Perucho, M., Hardee, Y. Y. Kovalev. P. E., Lobanov, A. P., Agudo, I., and Marti-Vidal, I.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Abstract

We make use of VLBI observations of the radio jet in the quasar S5 0836+710 at different frequencies and epochs to study its properties. The jet shows helical structure at all frequencies. The ridge-line of the emission in the jet coincides at all frequencies and epochs, within the errors. We conclude that the helicity is a real, physical structure. Small differences between epochs reveal wave-like motion of the ridge-line transversal to the jet propagation axis. These transversal motions are measured to be superluminal. This unphysical result could correspond to a possible small amplitude oscillation of the ridge-line at the radio-core and to large errors in the determination of the positions. In addition, higher resolution images at 15 GHz show that the ridge-line does not coincide exactly with the centre of the radio jet. At arc-second scales, this powerful jet shows non-collimated, irregular structure and a lack of a hot-spot. Following this collection of evidence, we conclude that the ridge-line could be related to a pressure maximum within the jet cross-section, associated with the observed helical pattern that could lead to jet disruption at longer scales. We discuss the implications regarding the nature of the instability and the jet flow itself., Comment: 6 pages. Proceedings of the 11th EVN Symposium. Bordeaux (France), October 2012

Published
2013

5. Catching the radio flare in CTA 102: II. VLBI kinematic analysis

Author

Fromm, C. M., Ros, E., Perucho, M., Savolainen, T., Mimica, P., Kadler, M., Lobanov, A. P., Lister, M. L., and Zensus, Y. Y. Kovalev \and J. A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We performed multifrequency multiepoch Very Long Baseline Array (VLBA) observations of the blazar CTA 102 during its 2006 radio flare, the strongest ever reported for this source. These observations provide an excellent opportunity to investigate the evolution of the physical properties of blazars, especially during these flaring events. We want to study the kinematic changes in the source during the strong radio outburst in April 2006 and test the assumption of a shock-shock interaction. This assumption is based on the analysis and modeling of the single-dish observations of CTA\,102 (Paper I). In this paper we study the kinematics of CTA 102 at several frequencies using VLBI observations. From the modeled jet features we derived estimates for the evolution of the physical parameters, such as the particle density and the magnetic field. Furthermore, we combined our observations during the 2006 flare with long-term VLBA monitoring of the source at 15 GHz and 43 GHz. We cross-identified seven features throughout our entire multifrequency observations and find evidence of two possible recollimation shocks around 0.1 mas (deprojected 18 pc at a viewing angle of 2.6 degrees) and 6.0 mas (deprojected 1 kpc) from the core. The 43 GHz observations reveal a feature ejected at epoch $t_\mathrm{ej}=2005.9\pm0.2$, which could be connected to the 2006 April radio flare. Furthermore, this feature might be associated with the traveling component involved in the possible shock-shock interaction, which gives rise to the observed double peak structure in the single-dish light curves reported in Paper I., Comment: 34 pages, 29 figures, A\& A accepted

Published
2012
Full Text
View/download PDF

7. Multiwavelength behaviour of the blazar 3C 279: decade-long study from γ-ray to radio

Author

V M Larionov, S G Jorstad, A P Marscher, M Villata, C M Raiteri, P S Smith, I Agudo, S S Savchenko, D A Morozova, J A Acosta-Pulido, M F Aller, H D Aller, T S Andreeva, A A Arkharov, R Bachev, G Bonnoli, G A Borman, V Bozhilov, P Calcidese, M I Carnerero, D Carosati, C Casadio, W-P Chen, G Damljanovic, A V Dementyev, A Di Paola, A Frasca, A Fuentes, J L Gómez, P Gónzalez-Morales, A Giunta, T S Grishina, M A Gurwell, V A Hagen-Thorn, T Hovatta, S Ibryamov, M Joshi, S Kiehlmann, J-Y Kim, G N Kimeridze, E N Kopatskaya, Yu A Kovalev, Y Y Kovalev, O M Kurtanidze, S O Kurtanidze, A Lähteenmäki, C Lázaro, L V Larionova, E G Larionova, G Leto, A Marchini, K Matsumoto, B Mihov, M Minev, M G Mingaliev, D Mirzaqulov, R V Muñoz Dimitrova, I Myserlis, A A Nikiforova, M G Nikolashvili, N A Nizhelsky, E Ovcharov, L D Pressburger, I A Rakhimov, S Righini, N Rizzi, K Sadakane, A C Sadun, M R Samal, R Z Sanchez, E Semkov, S G Sergeev, L A Sigua, L Slavcheva-Mihova, P Sola, Yu V Sotnikova, A Strigachev, C Thum, E Traianou, Yu V Troitskaya, I S Troitsky, P G Tsybulev, A A Vasilyev, O Vince, Z R Weaver, K E Williamson, and G V Zhekanis

Published
2020
Full Text
View/download PDF

11. Parsec-scale Properties of Steep- and Flat-spectrum Extragalactic Radio Sources from a VLBA Survey of a Complete North Polar Cap Sample

Author

A V Popkov, Y Y Kovalev, L Y Petrov, and Yu A Kovalev

Subjects
Astrophysics
Abstract

We observed with the Very Long Baseline Array (VLBA) at 2.3 and 8.6 GHz a complete flux-density-limited sample of 482 radio sources with decl. > +75° brighter than 200 mJy at 1.4 GHz drawn from the NVSS catalog. A total of 34% of the sources show parsec-scale emission above the flux density detection limit of 30 mJy; their accurate positions and parsec-scale structure parameters are determined. Among all the sources detected at least at the shortest VLBA baselines, the majority, or 72%, have a steep single-dish spectrum. The fraction of the sources with a detectable parsec-scale structure is above 95% among the flat-spectrum objects and close to 25% among the steep-spectrum objects. We identified 82 compact steep-spectrum source candidates, which make up 17% of the sample; most of them are reported for the first time. The compactness and the brightness temperature of the sources in our sample show a positive correlation with single-dish and VLBA spectral indices. All the sources with a significant 8 GHz variability were detected by the VLBA snapshot observations, which independently confirmed their compactness. We demonstrated that 54% of the sources detected by the VLBA at 2.3 GHz in our sample have a steep VLBA spectrum. The compact radio emission of these sources is likely dominated by optically thin jets or mini-lobes, not by an opaque jet core. These results show that future VLBI surveys aimed at searching for new sources with parsec-scale structure should include not only flat-spectrum sources but also steep-spectrum ones in order to reach an acceptable level of completeness.

Published
2021
Full Text
View/download PDF

13. Tracing Milky Way scattering by compact extragalactic radio sources

Author

T A Koryukova, A B Pushkarev, A V Plavin, and Y Y Kovalev

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We used archival very long baseline interferometry (VLBI) data of active galactic nuclei (AGN) observed from 1.4 GHz to 86 GHz to measure the angular size of VLBI radio cores in 8959 AGNs. We analysed their sky distributions, frequency dependencies and created the most densely sampled and complete to date distribution map of large-scale scattering properties of the interstellar medium in our Galaxy. Significant angular broadening of the measured AGN core sizes is detected for the sources seen through the Galactic plane, and this effect is especially strong at low frequencies (e.g., at 2 GHz). The scattering screens containing electron density fluctuations of hot plasma are mainly concentrated in the Galactic plane and manifest clumpy distribution. The region of the strongest scattering is the Galactic centre, where the Galactic bar and the compact radio source Sagittarius A* are located. We have also found the enhancement of scattering strength in regions of the Cygnus constellation, supernova remnants Taurus A, Vela, W78 and Cassiopeia A, and the Orion Nebula. Using multi-frequency observational data of AGN core sizes, we separated the contribution of the intrinsic and scattered sizes to the measured angular diameter for 1411 sources. For the sources observed through the Galactic plane, the contribution of the scattered size component is systematically larger than for those seen outside the Galactic plane. The derived power-law scattering indices are found to be in good agreement with theoretical predictions for the diffractive-dominated scattering of radio emission in a hot plasma with Gaussian distribution of density inhomogeneities., Comment: 15 pages, 14 figures, 7 tables, accepted to MNRAS

Published
2022

14. MOJAVE XXI. Decade-long linear polarization variability in AGN jets at parsec scales

Author

D I Zobnina, H D Aller, M F Aller, D C Homan, Y Y Kovalev, M L Lister, I N Pashchenko, A B Pushkarev, and T Savolainen

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Using stacking of images obtained at different epochs, we studied the variability properties of linear polarization of active galactic nucleus (AGN) jets on parsec-scales. Our sample is drawn from the MOJAVE programme, and consists of 436 AGNs manifesting core-jet morphology and having at least five VLBA observing epochs at 15 GHz from January 1996 through August 2019, with some additional archival VLBA data reduced by us. We employed a stacking procedure and constructed maps of (i) standard deviation of fractional polarization and electric vector position angle (EVPA) over epochs as the measure of variability and (ii) median polarization degree to quantify typical values in time. The distributions of these values along and across the jet were analysed for the whole sample for the first time. We found that core EVPA variability is typically higher than that of the jet, presumably due to component blending and outflow bends in the core. The BL Lacertae object cores have lower EVPA variability, compared to that of quasars, possibly due to lower Faraday rotation measure, suggesting a stronger ordered magnetic field component. The EVPA becomes more stable down the jet. Most of the sources showing this trend have a time coverage of more than 12 years and at least 15 epochs. The possible cause could be the increase of stability in the magnetic field direction, reflecting an increase in the fraction of the magnetic field that is ordered. There are no significant optical-class-dependent or spectral-class-dependent relations in the EVPA variability properties in AGN jets., 15 pages, 11 figures, 5 tables; accepted by MNRAS; full electronic tables are available as ancillary files

Published
2023

15. MOJAVE – XX. Persistent linear polarization structure in parsec-scale AGN jets

Author

A B Pushkarev, H D Aller, M F Aller, D C Homan, Y Y Kovalev, M L Lister, I N Pashchenko, T Savolainen, D I Zobnina, Crimean Astrophysical Observatory, University of Michigan, Ann Arbor, Denison University, RAS - P.N. Lebedev Physics Institute, Purdue University, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), polarization, general [quasars], Space and Planetary Science, general [BL Lacertae objects], Astrophysics of Galaxies (astro-ph.GA), active [galaxies], jets [galaxies], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, galaxies [radio continuum]
Abstract

We analysed the parsec-scale linear polarization properties of 436 active galactic nuclei (AGN) based on 15 GHz polarimetric Very Long Baseline Array (VLBA) observations. We present polarization and total intensity images averaged over at least five epochs since 1996 January 19 through 2019 August 4. Stacking improves the image sensitivity down to $\sim$30 $\mu$Jy/beam and effectively fills out the jet cross-section both in total intensity and linear polarization. It delineates the long-term persistent magnetic field configuration and its regularity by restoring spatial distributions of the electric vector position angle (EVPA) and fractional polarization, respectively. On average, about ten years of stacking period is needed to reveal the stable and most-complete polarization distribution of a source. We find that the degree of polarization significantly increases down and across the jet towards its edges, typically manifesting U or W-shaped transverse profiles, suggesting a presence of a large-scale helical magnetic field associated with the outflow. In some AGN jets, mainly BL Lacs, we detect quasi-constant fractional polarization profiles across the jet, accompanied by EVPAs that closely follow the outflow. BL Lacs show higher fractional polarization values in their cores and jets than those in quasars up to hectoparsec de-projected scales, while on larger scales, they become comparable. High-synchrotron-peaked BL Lac jets are found to be less polarized than intermediate and low-synchrotron-peaked BL Lacs. The spatial distribution of the EVPAs in BL Lacs tend to align with the local jet direction, while quasars show an excess of orthogonal polarization orientation., Comment: 18 pages, 16 figures, 5 tables; accepted by MNRAS; full electronic tables, animated movie and all Figure Set plots are available as ancillary files

Published
2023

17. Microarcsecond VLBI Pulsar Astrometry with PSRπ II. Parallax Distances for 57 Pulsars

Author

A. T. Deller, W. M. Goss, W. F. Brisken, S. Chatterjee, J. M. Cordes, G. H. Janssen, Y. Y. Kovalev, T. J. W. Lazio, L. Petrov, B. W. Stappers, and A. Lyne

Subjects
Astrophysics, Astronomy
Abstract

We present the results of PSRπ, a large astrometric project targeting radio pulsars using the Very Long Baseline Array (VLBA). From our astrometric database of 60 pulsars, we have obtained parallax-based distance measurements for all but 3, with a parallax precision that is typically ∼45 μas and approaches 10 μas in the best cases. Our full sample doubles the number of radio pulsars with a reliable (≳5σ) model-independent distance constraint. Importantly, many of the newly measured pulsars are well outside the solar neighborhood, and so PSRπ brings a near-tenfold increase in the number of pulsars with a reliable model-independent distance at d > 2 kpc. Our results show that both widely used Galactic electron density distribution models contain significant shortcomings, particularly at high Galactic latitudes. When comparing our results to pulsar timing, two of the four millisecond pulsars in our sample exhibit significant discrepancies in their proper motion estimates. With additional VLBI observations that extend our sample and improve the absolute positional accuracy of our reference sources, we will be able to additionally compare pulsar absolute reference positions between VLBI and timing, which will provide a much more sensitive test of the correctness of the solar system ephemerides used for pulsar timing. Finally, we use our large sample to estimate the typical accuracy attainable for differential VLBA astrometry of pulsars, showing that for sufficiently bright targets observed eight times over 18 months, a parallax uncertainty of 4 μas per arcminute of separation between the pulsar and calibrator can be expected.

Published
2019
Full Text
View/download PDF

18. Parsec-scale properties of the peculiar gigahertz-peaked spectrum quasar 0858−279

Author

N A Kosogorov, Y Y Kovalev, M Perucho, and Yu A Kovalev

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract

We performed multi-frequency studies on the gigahertz-peaked spectrum high-redshift quasar 0858-279. Initially, the source presented itself in the early VLBI images as a very peculiar resolved blob. We observed the quasar with the VLBA at 1.4-24 GHz in a dual-polarization mode. The high spatial resolution and the spectral index maps enabled us to resolve the core-jet structure and locate a weak and compact core by its inverted spectrum. The dominant jet component 20 parsecs away from the core was optically thin above 10 GHz and opaque below it. We also estimated an uncommonly strong magnetic field in the bright jet feature, which turned out to be around 1 G. The Faraday rotation measure maps revealed high RM values over 6000 rad/m^2. Additionally, these maps allowed us to follow the magnetic field direction in the bright jet feature being perpendicular to the propagation direction of the jet. All the results strongly indicated the formation of a shock wave in the dominant component arising from an interaction with the surrounding matter. Using the proposed hypothesis and the core shift approach, we discovered that the magnetic field in the core region is of the order of 0.1 G., Comment: 15 pages, 12 figures, accepted for publication in MNRAS

Published
2021

19. Growing evidence for high-energy neutrinos originating in radio blazars

Author

A V Plavin, Y Y Kovalev, Yu A Kovalev, and S V Troitsky

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Evidence for bright radio blazars being high-energy neutrino sources was found in recent years. However, specifics of how and where these particles get produced still need to be determined. In this paper, we add 14 new IceCube events from 2020-2022 to update our analysis of the neutrino-blazars connection. We test and refine earlier findings by utilising the total of 71 track-like high-energy IceCube events from 2009-2022. We correlate them with the complete sample of 3412 extragalactic radio sources selected by their compact radio emission. We demonstrate that neutrinos are statistically associated with radio-bright blazars with a post-trial p-value of 3*10^-4. In addition to this statistical study, we confirm previous individual neutrino-blazar associations, find and discuss several new ones. Notably, PKS 1741-038 was selected earlier and had a second neutrino detected from its direction in 2022; PKS 0735+168 has experienced a major flare across the whole electromagnetic spectrum coincidently with a neutrino arrival from that direction in 2021., 10 pages, 5 figures, 2 machine-readable tables; V2: minor changes and updates, accepted by MNRAS

Published
2022

22. A POSSIBLE REASON OF FORMING THE VARIOUS TYPE OF SPECTRA IN EXTRAGALACTIC OBJECTS

Author

Yu. A. Kovalev and Y. Y. Kovalev

Subjects
Astronomy, QB1-991
Abstract

An analysis of multifrequency observations of 1,300 instantaneous spectra at cantimeter-decimeter waves during 7 sets for a sample of up to 200 VLBI-compact objects gives a strong experimental evidence to an old hypothesis, that a VLBI-compact jet of relativistic particles from an object's nucleus is a main reason of forming the various type of spectra inextragalactic objects. It is enough to explain all main known spectra types (steep, flattened, inverted) by two spectra components only- of a quasi stationary jet in a longitudinal magnetic field and an optically thin cloud or envelope, resulted by the jet. A combination of thesetwo components gives also complex shapes in a case of a nonstationary phase of the jet.

Published
2017
Full Text
View/download PDF

23. JETS IN 20 AGNS WITH STRONG LONG-TERM VARIABILITY OF 1 - 22 GHZ SPECTRA

Author

Yu. A. Kovalev, A. B. Berlin, Y. Y. Kovalev, and N. A. Nizhelsky

Subjects
Astronomy, QB1-991
Abstract

Results of multifrequency broad band spectra observations and their interpretations by the Hedgehog relativistic jet model are presented for 20 strong variable radio sources. The many years strong variability of well known objects, including BL Lac and OJ 287 for 20 years, is analyzed. Instantaneous 5-7 frequency spectra were measured at the RATAN-600 radio telescope over the period from 1979 to 1999. The strong long-term variability of the spectra is explained by the variability of a continuous relativistic jet with a variable ejection of it from an active nucleus in quasi radial magnetic field.

Published
2017
Full Text
View/download PDF

24. Polarimetric Properties of Event Horizon Telescope Targets from ALMA

Author

Ciriaco Goddi, Iván Martí-Vidal, Hugo Messias, Geoffrey C. Bower, Avery E. Broderick, Jason Dexter, Daniel P. Marrone, Monika Moscibrodzka, Hiroshi Nagai, Juan Carlos Algaba, Keiichi Asada, Geoffrey B. Crew, José L. Gómez, C. M. Violette Impellizzeri, Michael Janssen, Matthias Kadler, Thomas P. Krichbaum, Rocco Lico, Lynn D. Matthews, Antonios Nathanail, Angelo Ricarte, Eduardo Ros, Ziri Younsi, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Richard Anantua, 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, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Dominique Broguiere, Thomas Bronzwaer, Do-Young Byun, John E. Carlstrom, Andrew Chael, Chi-kwan Chan, Shami Chatterjee, Koushik Chatterjee, Ming-Tang Chen, Yongjun Chen, Paul M. Chesler, Ilje Cho, Pierre Christian, John E. Conway, James M. Cordes, Thomas M. Crawford, Alejandro Cruz-Osorio, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Sheperd S. Doeleman, Ralph P. Eatough, 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, Roman Gold, Arturo I. Gómez-Ruiz, 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, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, 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, Michael Kramer, Carsten Kramer, Cheng-Yu Kuo, Tod R. Lauer, Sang-Sung Lee, Aviad Levis, Yan-Rong Li, Zhiyuan Li, Michael Lindqvist, 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, Alan P. Marscher, Satoki Matsushita, Lia Medeiros, Karl M. Menten, Izumi Mizuno, Yosuke Mizuno, James M. Moran, Kotaro Moriyama, Cornelia Müller, Gibwa Musoke, Alejandro Mus Mejías, Neil M. Nagar, Masanori Nakamura, Ramesh Narayan, Gopal Narayanan, Iniyan Natarajan, Joey Neilsen, Roberto Neri, Chunchong Ni, Aristeidis Noutsos, Michael A. Nowak, Hiroki Okino, Héctor Olivares, Gisela N. Ortiz-León, Tomoaki Oyama, Feryal Özel, 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, Ben Prather, Jorge A. Preciado-López, Dimitrios Psaltis, Hung-Yi Pu, Venkatessh Ramakrishnan, Ramprasad Rao, Mark G. Rawlings, Alexander W. Raymond, Luciano Rezzolla, Bart Ripperda, Freek Roelofs, Alan Rogers, 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, Tyler Trent, Efthalia Traianou, 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, Maciek Wielgus, George N. Wong, Qingwen Wu, Doosoo Yoon, André Young, Ken Young, Feng Yuan, Ye-Fei Yuan, J. Anton Zensus, Guang-Yao Zhao, Shan-Shan Zhao, Gabriele Bruni, A. Gopakumar, Antonio Hernández-Gómez, Ruben Herrero-Illana, Adam Ingram, S. Komossa, Y. Y. Kovalev, Dirk Muders, Manel Perucho, Florian Rösch, Mauri Valtonen, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Academy of Finland, European Commission, Harvard University, Agencia Nacional de Investigación y Desarrollo (Chile), Comisión Nacional de Investigación Científica y Tecnológica (Chile), Consejo Nacional de Ciencia y Tecnología (México), Universidad Nacional Autónoma de México, European Research Council, Generalitat Valenciana, Ministerio de Ciencia e Innovación (España), Gordon and Betty Moore Foundation, Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Science and Technology (Taiwan), National Aeronautics and Space Administration (US), National Key Research and Development Program (China), National Science Foundation (US), National Natural Science Foundation of China, National Research Foundation of Korea, Netherlands Organization for Scientific Research, Swedish Research Council, Ministerio de Economía y Competitividad (España), Junta de Andalucía, National Nuclear Security Administration (US), Ministero dell'Istruzione, dell'Università e della Ricerca, Ministerio de Ciencia, Innovación y Universidades (España), China Postdoctoral Science Foundation, Consejo Superior de Investigaciones Científicas (España), Astronomy, Goddi, Ciriaco, Martí-Vidal, Iván, Messias, Hugo, Bower, Geoffrey C., Broderick, Avery E., Dexter, Jason, Marrone, Daniel P., Moscibrodzka, Monika, Nagai, Hiroshi, Algaba, Juan Carlo, Asada, Keiichi, Crew, Geoffrey B., Gómez, José L., Impellizzeri, C. M. Violette, Janssen, Michael, Kadler, Matthia, Krichbaum, Thomas P., Lico, Rocco, Matthews, Lynn D., Nathanail, Antonio, Ricarte, Angelo, Ros, Eduardo, Younsi, Ziri, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Anantua, Richard, 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., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thoma, 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., Cruz-Osorio, Alejandro, Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Doeleman, Sheperd S., Eatough, Ralph P., 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., García, Roberto, Gentaz, Olivier, Georgiev, Bori, Gold, Roman, Gómez-Ruiz, Arturo I., 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., Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., 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, Michael, Kramer, Carsten, Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Levis, Aviad, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, 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, Marscher, Alan P., Matsushita, Satoki, Medeiros, Lia, Menten, Karl M., Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Müller, Cornelia, Musoke, Gibwa, Mejías, Alejandro Mu, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidi, Nowak, Michael A., Okino, Hiroki, Olivares, Héctor, Ortiz-León, Gisela N., Oyama, Tomoaki, Özel, Feryal, 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., Prather, Ben, Preciado-López, Jorge A., Psaltis, Dimitrio, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez, Salvador, Sánchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuoma, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, De, 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, Bemmel, Ilse van, 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, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guang-Yao, Zhao, Shan-Shan, Bruni, Gabriele, Gopakumar, A., Hernández-Gómez, Antonio, Herrero-Illana, Ruben, Ingram, Adam, Komossa, S., Kovalev, Y. Y., Muders, Dirk, Perucho, Manel, Rösch, Florian, Valtonen, Mauri, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
010504 meteorology & atmospheric sciences, Astronomy, Astrophysics - astrophysics of galaxies, Astrophysics, Astrophysics - high energy astrophysical phenomena, 01 natural sciences, Radio galaxies, Supermassive black holes, Radio jets, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Linear polarization, Polarization (waves), Wavelength, Long baseline interferometry, 994, 1390, 16, 1347, 1278, 808, 932, 565, 1663, 164, 1343, 1319, Magnitude (astronomy), symbols, Astrophysics - instrumentation and methods for astrophysics, FOS: Physical sciences, F500, Galactic center, symbols.namesake, Polarimetry, 0103 physical sciences, Faraday effect, Very-long-baseline interferometry, Quasars, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Event Horizon Telescope, Active galactic nuclei, Photosphere, Astronomy and Astrophysics, Interferometry, 13. Climate action, Space and Planetary Science, Magnetic fields, Astrophysics of Galaxies (astro-ph.GA), Relativistic jets, Blazars
Abstract

Full list of authors: Goddi, Ciriaco; Martí-Vidal, Iván; Messias, Hugo; Bower, Geoffrey C.; Broderick, Avery E.; Dexter, Jason; Marrone, Daniel P.; Moscibrodzka, Monika; Nagai, Hiroshi; Algaba, Juan Carlos; Asada, Keiichi; Crew, Geoffrey B.; Gómez, José L.; Impellizzeri, C. M. Violette; Janssen, Michael; Kadler, Matthias; Krichbaum, Thomas P.; Lico, Rocco; Matthews, Lynn D.; Nathanail, Antonios Ricarte, Angelo; Ros, Eduardo; Younsi, Ziri; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Anantua, Richard; 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.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; 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.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Doeleman, Sheperd S.; Eatough, Ralph P.; 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.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Gold, Roman; Gómez-Ruiz, Arturo I.; 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.; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; 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, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Levis, Aviad; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; 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; Marscher, Alan P.; Matsushita, Satoki; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Müller, Cornelia; Musoke, Gibwa; Mejías, Alejandro Mus; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; 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.; 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; 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; 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; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guang-Yao; Zhao, Shan-Shan; Bruni, Gabriele; Gopakumar, A.; Hernández-Gómez, Antonio; Herrero-Illana, Ruben; Ingram, Adam; Komossa, S.; Kovalev, Y. Y.; Muders, Dirk; Perucho, Manel; Rösch, Florian; Valtonen, Mauri.-- This is an open access article, 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., We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the λ3 mm and λ1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%–15%) and large rotation measures (RM > 103.3–105.5 rad m−2), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (−4.2 ± 0.3) × 105 rad m−2 at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (–2.1 ± 0.1) × 105 rad m−2 at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from −1.2 to 0.3 × 105 rad m−2 at 3 mm and −4.1 to 1.5 × 105 rad m−2 at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA. © 2021. The American Astronomical Society., ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, andNational 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 Letter makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.00413.V ADS/JAO.ALMA#2016. 1.01116.V ADS/JAO.ALMA#2016.1.01216.V ADS/JAO. ALMA#2016.1.01114.V ADS/JAO.ALMA#2016.1.01154.V ADS/JAO.ALMA#2016.1.01176.V ADS/JAO.ALMA#2016. 1.01198.V ADS/JAO.ALMA#2016.1.01290.V ADS/JAO. ALMA#2016.1.01404.V ADS/JAO.ALMA#2017.1.00841.V ADS/JAO.ALMA#2013.1.01022.S ADS/JAO.ALMA#2015. 1.01170.S ADS/JAO.ALMA#2016.1.00415.S ADS/JAO. ALMA#2017.1.00608.S The authors of the present Letter thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496, 315721); 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; 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; Agencia Nacional de Investigacion y Desarrollo (ANID), Chile via NCN19_058 (TITANs) and Fondecyt 3190878; Consejo Nacional de Ciencia y Tecnologia (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; Direccion General de Asuntos del Personal AcademicoUniversidad Nacional Autonoma de Mexico (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 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); 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-SSWSLH057, QYZDJSSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the MaxPlanck-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 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 (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107-2119-M-001020, and 107-2119-M-110-005, MOST 108-2112-M-001-048 and MOST 109-2124-M-001-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527, and Hubble Fellowship grant HST-HF251431.001-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-1337663, AST-1440254, AST-1555365, AST-1615796, AST-1715061, AST-1716327, AST-1716536, OISE-1743747, AST-1816420, AST-1903847, AST-1935980, AST-2034306); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007, 11991052, 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, 2015R1D1A1A01056807, 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 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 Economia y Competitividad (grants PGC2018098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21); 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 Consejeria de Economia, Conocimiento, Empresas y Universidad of the Junta de Andalucia (grant P18-FR-1769), the Consejo Superior de Investigaciones Cientificas (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 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; NASA NuSTAR award 80NSSC20K0645; Chandra award DD7-18089X. 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 in the GMVA and EHT, correlation centers, and institutions for their enthusiastic support. The GMVA is coordinated by the VLBI group at the Max-Planck-Institut fur Radioastronomie (MPIfR) and consists of telescopes operated by MPIfR, IRAM, Onsala, Metsahovi, Yebes, the Korean VLBI Network, the Green Bank Observatory and the VLBA. APEX is a collaboration between the MPIfR (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 thank Sergio Martin for the help interpreting the Sgr A* spectrum in SPW= 2. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. M.P. acknowledges support by the Spanish Ministry of Science through Grants PID2019-105510GB-C31, and PID2019-107427GB-C33, and from the Generalitat Valenciana through grant PROMETEU/2019/071.

Published
2021

25. MOJAVE XIX: Brightness Temperatures and Intrinsic Properties of Blazar Jets

Author

D. C. Homan, M. H. Cohen, T. Hovatta, K. I. Kellermann, Y. Y. Kovalev, M. L. Lister, A. V. Popkov, A. B. Pushkarev, E. Ros, T. Savolainen, Denison University, California Institute of Technology, Metsähovi Radio Observatory, National Radio Astronomy Observatory Socorro, Max-Planck-Institut für Radioastronomie, Purdue University, Lebedev Physical Institute, Crimean Astrophysical Observatory, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
ACTIVE GALACTIC NUCLEI, SPECTRUM RADIO-SOURCES, TELESCOPE OPTICAL SPECTROSCOPY, EMISSION-LINE PROFILES, DATA RELEASE, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, complex mixtures, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astronomy and Astrophysics, equipment and supplies, BL-LACERTAE OBJECTS, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, ENERGY GAMMA-RAYS, Astrophysics of Galaxies (astro-ph.GA), LAC OBJECTS, DIGITAL SKY SURVEY, COMPLETE SAMPLE, Astrophysics - High Energy Astrophysical Phenomena, circulatory and respiratory physiology
Abstract

We present multi-epoch, parsec-scale core brightness temperature observations of 447 AGN jets from the MOJAVE and 2cm Survey programs at 15 GHz from 1994 to 2019. The brightness temperature of each jet over time is characterized by its median value and variability. We find that the range of median brightness temperatures for AGN jets in our sample is much larger than the variations within individual jets, consistent with Doppler boosting being the primary difference between the brightness temperatures of jets in their median state. We combine the observed median brightness temperatures with apparent jet speed measurements to find the typical intrinsic Gaussian brightness temperature of (4.1 +- 0.6)*10^10 K, suggesting that jet cores are at or below equipartition between particle and magnetic field energy in their median state. We use this value to derive estimates for the Doppler factor for every source in our sample. For the 309 jets with both apparent speed and brightness temperature data, we estimate their Lorentz factors and viewing angles to the line of sight. Within the BL Lac optical class, we find that high-synchrotron-peaked (HSP) BL Lacs have smaller Doppler factors, lower Lorentz factors, and larger angles to the line of sight than intermediate and low-synchrotron-peaked (LSP) BL Lacs. We confirm that AGN jets with larger Doppler factors measured in their parsec-scale radio cores are more likely to be detected in gamma rays, and we find a strong correlation between gamma-ray luminosity and Doppler factor for the detected sources., Comment: 29 pages, 16 figures, 4 tables; accepted by ApJ; full electronic tables and all Figure Set plots are available as ancillary files

Published
2021
Full Text
View/download PDF

26. Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron IV. The quasar 3C 345 at 18 cm: Magnetic field structure and brightness temperature

Author

Eduardo Ros, Andrei Lobanov, Felix M. Pötzl, Mikhail M. Lisakov, David L. Jauncey, Antonio Fuentes, Gabriele Bruni, J. A. Zensus, José L. Gómez, Leonid I. Gurvits, Y. Y. Kovalev, U. Bach, Tuomas Savolainen, E. V. Kravchenko, Kirill Sokolovsky, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Junta de Andalucía, Russian Science Foundation, Academy of Finland, Consejo Superior de Investigaciones Científicas (España), Max Planck Institute for Radio Astronomy, CSIC, National Institute for Astrophysics, Delft University of Technology, CSIRO, Moscow Institute of Physics and Technology, Anne Lähteenmäki Group, Michigan State University, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
Brightness, Active galactic nucleus, 010504 meteorology & atmospheric sciences, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, galaxies [Radio continuum], Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Radio continuum: galaxies, Radio telescope, 0103 physical sciences, Very-long-baseline interferometry, 010303 astronomy & astrophysics, individual: 3C 345 [Quasars], Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Supermassive black hole, Jet (fluid), Galaxies: magnetic fields, magnetic fields [Galaxies], Astronomy and Astrophysics, Quasar, Galaxies: active, 13. Climate action, Space and Planetary Science, Galaxies: jets, Brightness temperature, jets [Galaxies], Astrophysics - High Energy Astrophysical Phenomena, Quasars: individual: 3C 345
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., Context. Supermassive black holes in the centres of radio-loud active galactic nuclei (AGN) can produce collimated relativistic outflows (jets). Magnetic fields are thought to play a key role in the formation and collimation of these jets, but the details are much debated. Aims. We study the innermost jet morphology and magnetic field strength in the AGN 3C 345 with an unprecedented resolution using images obtained within the framework of the key science programme on AGN polarisation of the Space VLBI mission RadioAstron. Methods. We observed the flat spectrum radio quasar 3C 345 at 1.6 GHz on 2016 March 30 with RadioAstron and 18 ground-based radio telescopes in full polarisation mode. Results. Our images, in both total intensity and linear polarisation, reveal a complex jet structure at 300 μas angular resolution, corresponding to a projected linear scale of about 2 pc or a few thousand gravitational radii. We identify the synchrotron self-absorbed core at the jet base and find the brightest feature in the jet 1.5 mas downstream of the core. Several polarised components appear in the Space VLBI images that cannot be seen from ground array-only images. Except for the core, the electric vector position angles follow the local jet direction, suggesting a magnetic field perpendicular to the jet. This indicates the presence of plane perpendicular shocks in these regions. Additionally, we infer a minimum brightness temperature at the largest (u, v)-distances of 1.1 × 1012 K in the source frame, which is above the inverse Compton limit and an order of magnitude larger than the equipartition value. This indicates locally efficient injection or re-acceleration of particles in the jet to counter the inverse Compton cooling or the geometry of the jet creates significant changes in the Doppler factor, which has to be > 11 to explain the high brightness temperatures. © F. M. Pötzl et al. 2021., The National Radio Astronomy Observatory and the Green Bank Observatory are facilities of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has made use of data from the MOJAVE database that is maintained by the MOJAVE team (Lister et al. 2018). Partly based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg. The data were correlated at the DiFX correlator (Deller et al. 2011; Bruni et al. 2016) of the MPIfR at Bonn. A. P. L., Y. Y. K., and E. V. K. were supported by the Russian Science Foundation (project 20-62-46021). L. I. G. acknowledges support by the CSIRO Distinguished Visitor Programme. T. S. was supported by the Academy of Finland projects 274477 and 315721. J. L. G. acknowledges the support of the Spanish Ministerio de Economía y Competitividad (grants AYA2016-80889-P, PID2019-108995GB-C21), 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), and 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). This research has made use of NASA’s Astrophysics Data System. This research has made use of adstex (https://github.com/yymao/adstex). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Published
2021
Full Text
View/download PDF

27. An oversized magnetic sheath wrapping around the parsec-scale jet in 3C 273

Author

Y. Y. Kovalev, Matthew L. Lister, Alexander B. Pushkarev, Tuomas Savolainen, E. V. Kravchenko, and Mikhail M. Lisakov

Subjects
Active galactic nucleus, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, symbols.namesake, Astrophysical jet, law, 0103 physical sciences, Faraday effect, Faraday cage, 010303 astronomy & astrophysics, Very Long Baseline Array, 0105 earth and related environmental sciences, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Magnetic field, Transverse plane, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), symbols, High Energy Physics::Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract

In recent studies, several AGN have exhibited gradients of the Faraday Rotation Measure (RM) transverse to their parsec-scale jet direction. Faraday rotation likely occurs as a result of a magnetized sheath wrapped around the jet. In the case of 3C 273, using Very Long Baseline Array multi-epoch observations at 5, 8 and 15 GHz in 2009--2010, we observe that the jet RM has changed significantly towards negative values compared with that previously observed. These changes could be explained by a swing of the parsec-scale jet direction which causes synchrotron emission to pass through different portions of the Faraday screen. We develop a model for the jet-sheath system in 3C 273 where the sheath is wider than the single-epoch narrow relativistic jet. We present our oversized sheath model together with a derived wide jet full intrinsic opening angle $\alpha_\mathrm{int}=2.1^\circ$ and magnetic field strength $B_{||}=3$ $\mu$G and thermal particle density $N_\mathrm{e}=125~\mathrm{cm}^{-3}$ at the wide jet--sheath boundary 230 pc downstream (deprojected) from its beginning. Most of the Faraday rotation occurs within the innermost layers of the sheath. The model brings together the jet direction swing and long-term RM evolution and may be applicable to other AGN jets that exhibit changes of their apparent jet direction., Comment: 10 pages, 9 figures. Accepted to the Astrophysical Journal

Published
2021
Full Text
View/download PDF

28. The simultaneous low state spectral energy distribution of 1ES 2344+514 from radio to very high energies

Author

MAGIC Collaboration, J. Aleksić(IFAE, Edifici Cn., Campus UAB, Spain), L. A. Antonelli(INAF National Institute for Astrophysics, Rome, Italy), P. Antoranz(Università di Siena, and INFN Pisa, Italy), M. Asensio(Universidad Complutense, Spain), M. Backes(Technische Universität Dortmund, Germany), U. Barres de Almeida(Max-Planck-Institut für Physik, München, Germany), J. A. Barrio(Universidad Complutense, Spain), W. Bednarek(University of Łódź, Poland), K. Berger(Inst. de Astrofísica de Canarias, Tenerife, Spain), E. Bernardini(Deutsches Elektronen-Synchrotron), A. Biland(ETH Zurich, Switzerland), O. Blanch(IFAE, Edifici Cn., Campus UAB, Spain), R. K. Bock(Max-Planck-Institut für Physik, München, Germany), A. Boller(ETH Zurich, Switzerland), S. Bonnefoy(Universidad Complutense, Spain), G. Bonnoli(INAF National Institute for Astrophysics, Rome, Italy), D. Borla Tridon(Max-Planck-Institut für Physik, München, Germany), T. Bretz(Universität Würzburg, Germany), E. Carmona(Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Spain), A. Carosi(INAF National Institute for Astrophysics, Rome, Italy), D. Carreto Fidalgo(Universität Würzburg, Germany), P. Colin(Max-Planck-Institut für Physik, München, Germany), E. Colombo(Inst. de Astrofísica de Canarias, Tenerife, Spain), J. L. Contreras(Universidad Complutense, Spain), J. Cortina(IFAE, Edifici Cn., Campus UAB, Spain), L. Cossio(Università di Udine, and INFN Trieste, Italy), S. Covino(INAF National Institute for Astrophysics, Rome, Italy), P. Da Vela(Università di Siena, and INFN Pisa, Italy), F. Dazzi(Università di Udine, and INFN Trieste, Italy), A. De Angelis(Università di Udine, and INFN Trieste, Italy), G. De Caneva(Deutsches Elektronen-Synchrotron), B. De Lotto(Università di Udine, and INFN Trieste, Italy), C. Delgado Mendez(Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Spain), M. Doert(Technische Universität Dortmund, Germany), A. Domínguez(Inst. de Astrofísica de Andalucía), D. Dominis Prester(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), D. Dorner(Universität Würzburg, Germany), M. Doro(Universitat Autònoma de Barcelona, Spain), D. Eisenacher(Universität Würzburg, Germany), D. Elsaesser(Universität Würzburg, Germany), D. Ferenc(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), M. V. Fonseca(Universidad Complutense, Spain), L. Font(Universitat Autònoma de Barcelona, Spain), C. Fruck(Max-Planck-Institut für Physik, München, Germany), R. J. García López(Inst. de Astrofísica de Canarias, Tenerife, Spain), M. Garczarczyk(Inst. de Astrofísica de Canarias, Tenerife, Spain), D. Garrido Terrats(Universitat Autònoma de Barcelona, Spain), M. Gaug(Universitat Autònoma de Barcelona, Spain), G. Giavitto(IFAE, Edifici Cn., Campus UAB, Spain), N. Godinović(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), A. González Muñoz(IFAE, Edifici Cn., Campus UAB, Spain), S. R. Gozzini(Deutsches Elektronen-Synchrotron), A. Hadamek(Technische Universität Dortmund, Germany), D. Hadasch(Institut de Ciències de l'Espai), A. Herrero(Inst. de Astrofísica de Canarias, Tenerife, Spain), J. Hose(Max-Planck-Institut für Physik, München, Germany), D. Hrupec(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), F. Jankowski(Deutsches Elektronen-Synchrotron), V. Kadenius(Tuorla Observatory, University of Turku, Finland), S. Klepser(IFAE, Edifici Cn., Campus UAB, Spain), M. L. Knoetig(Max-Planck-Institut für Physik, München, Germany), T. Krähenbühl(ETH Zurich, Switzerland), J. Krause(Max-Planck-Institut für Physik, München, Germany), J. Kushida(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), A. La Barbera(INAF National Institute for Astrophysics, Rome, Italy), D. Lelas(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), E. Leonardo(Università di Siena, and INFN Pisa, Italy), N. Lewandowska(Universität Würzburg, Germany), E. Lindfors(Tuorla Observatory, University of Turku, Finland), S. Lombardi(INAF National Institute for Astrophysics, Rome, Italy), M. López(Universidad Complutense, Spain), R. López-Coto(IFAE, Edifici Cn., Campus UAB, Spain), A. López-Oramas(IFAE, Edifici Cn., Campus UAB, Spain), E. Lorenz(Max-Planck-Institut für Physik, München, Germany), I. Lozano(Universidad Complutense, Spain), M. Makariev(Inst. for Nucl. Research and Nucl. Energy, Sofia, Bulgaria), K. Mallot(Deutsches Elektronen-Synchrotron), G. Maneva(Inst. for Nucl. Research and Nucl. Energy, Sofia, Bulgaria), N. Mankuzhiyil(Università di Udine, and INFN Trieste, Italy), K. Mannheim(Universität Würzburg, Germany), L. Maraschi(INAF National Institute for Astrophysics, Rome, Italy), B. Marcote(Universitat de Barcelona), M. Mariotti(Università di Padova and INFN Padova, Italy), M. Martínez(IFAE, Edifici Cn., Campus UAB, Spain), J. Masbou(Università di Padova and INFN Padova, Italy), D. Mazin(Max-Planck-Institut für Physik, München, Germany), M. Meucci(Università di Siena, and INFN Pisa, Italy), J. M. Miranda(Università di Siena, and INFN Pisa, Italy), R. Mirzoyan(Max-Planck-Institut für Physik, München, Germany), J. Moldón(Universitat de Barcelona), A. Moralejo(IFAE, Edifici Cn., Campus UAB, Spain), P. Munar-Adrover(Universitat de Barcelona), D. Nakajima(Max-Planck-Institut für Physik, München, Germany), A. Niedzwiecki(University of Łódź, Poland), D. Nieto(Universidad Complutense, Spain), K. Nilsson(Tuorla Observatory, University of Turku, Finland), N. Nowak(Max-Planck-Institut für Physik, München, Germany), R. Orito(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), S. Paiano(Università di Padova and INFN Padova, Italy), M. Palatiello(Università di Udine, and INFN Trieste, Italy), D. Paneque(Max-Planck-Institut für Physik, München, Germany), R. Paoletti(Università di Siena, and INFN Pisa, Italy), J. M. Paredes(Universitat de Barcelona), S. Partini(Università di Siena, and INFN Pisa, Italy), M. Persic(Università di Udine, and INFN Trieste, Italy), M. Pilia(Università dell'Insubria, Como, Italy), F. Prada(Inst. de Astrofísica de Andalucía), P. G. Prada Moroni(Università di Pisa, and INFN Pisa, Italy), E. Prandini(Università di Padova and INFN Padova, Italy), I. Puljak(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), I. Reichardt(IFAE, Edifici Cn., Campus UAB, Spain), R. Reinthal(Tuorla Observatory, University of Turku, Finland), W. Rhode(Technische Universität Dortmund, Germany), M. Ribó(Universitat de Barcelona), J. Rico(ICREA, Barcelona, Spain), S. Rügamer(Universität Würzburg, Germany), A. Saggion(Università di Padova and INFN Padova, Italy), K. Saito(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), T. Y. Saito(Max-Planck-Institut für Physik, München, Germany), M. Salvati(INAF National Institute for Astrophysics, Rome, Italy), K. Satalecka(Universidad Complutense, Spain), V. Scalzotto(Università di Padova and INFN Padova, Italy), V. Scapin(Universidad Complutense, Spain), C. Schultz(Università di Padova and INFN Padova, Italy), T. Schweizer(Max-Planck-Institut für Physik, München, Germany), S. N. Shore(Università di Pisa, and INFN Pisa, Italy), A. Sillanpää(Tuorla Observatory, University of Turku, Finland), J. Sitarek(IFAE, Edifici Cn., Campus UAB, Spain), I. Snidaric(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), D. Sobczynska(University of Łódź, Poland), F. Spanier(Universität Würzburg, Germany), S. Spiro(INAF National Institute for Astrophysics, Rome, Italy), V. Stamatescu(IFAE, Edifici Cn., Campus UAB, Spain), A. Stamerra(Università di Siena, and INFN Pisa, Italy), B. Steinke(Max-Planck-Institut für Physik, München, Germany), J. Storz(Universität Würzburg, Germany), S. Sun(Max-Planck-Institut für Physik, München, Germany), T. Surić(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), L. Takalo(Tuorla Observatory, University of Turku, Finland), H. Takami(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), F. Tavecchio(INAF National Institute for Astrophysics, Rome, Italy), P. Temnikov(Inst. for Nucl. Research and Nucl. Energy, Sofia, Bulgaria), T. Terzić(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, Croatia), D. Tescaro(Inst. de Astrofísica de Canarias, Tenerife, Spain), M. Teshima(Max-Planck-Institut für Physik, München, Germany), O. Tibolla(Universität Würzburg, Germany), D. F. Torres(ICREA, Barcelona, Spain), T. Toyama(Max-Planck-Institut für Physik, München, Germany), A. Treves(Università dell'Insubria, Como, Italy), M. Uellenbeck(Technische Universität Dortmund, Germany), P. Vogler(ETH Zurich, Switzerland), R. M. Wagner(Max-Planck-Institut für Physik, München, Germany), Q. Weitzel(ETH Zurich, Switzerland), F. Zandanel(Inst. de Astrofísica de Andalucía), R. Zanin(Universitat de Barcelona), The MAGIC Collaboration(Università di Trieste, and INFN Trieste, Italy), F. Longo(Università di Trieste, and INFN Trieste, Italy), F. Lucarelli(Agenzia Spaziale Italiana), C. Pittori(Agenzia Spaziale Italiana), S. Vercellone(INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Italy), for the AGILE team(Università di Padova and INFN Padova, Italy), D. Bastieri(Università di Padova and INFN Padova, Italy), C. Sbarra(INFN Padova, Italy), for the Fermi-LAT Collaboration(Max-Planck-Institut für Radioastronomie, Germany), E. Angelakis(Max-Planck-Institut für Radioastronomie, Germany), L. Fuhrmann(Max-Planck-Institut für Radioastronomie, Germany), I. Nestoras(Max-Planck-Institut für Radioastronomie, Germany), T. P. Krichbaum(Max-Planck-Institut für Radioastronomie, Germany), A. Sievers(Instituto de Radio Astronoma Milimétrica, Spain), J. A. Zensus(Max-Planck-Institut für Radioastronomie, Germany), for the F-GAMMA program(Crimean Astrophysical Observatory, Ukraine), K. A. Antonyuk(Crimean Astrophysical Observatory, Ukraine), W. Baumgartner(Astrophysics Science Division, NASA Goddard Space Flight Center, USA), A. Berduygin(Tuorla Observatory, University of Turku, Finland), M. Carini(Department of Physics and Astronomy, Western Kentucky University, USA), K. Cook(Department of Physics and Astronomy, Western Kentucky University, USA), N. Gehrels(Astrophysics Science Division, NASA Goddard Space Flight Center, USA), M. Kadler(Universität Würzburg, Germany), Yu. A. Kovalev(Astro Space Center of Lebedev Physical Institute, 117997 Moscow, Russia), Y. Y. Kovalev(Astro Space Center of Lebedev Physical Institute, 117997 Moscow, Russia), F. Krauss(Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, Germany), H. A. Krimm(Universities Space Research Association, Columbia, MD 21044, USA), A. Lähteenmäki(Aalto University Metsähovi Radio Observatory, Finland), M. L. Lister(Department of Physics, Purdue University, USA), W. Max-Moerbeck(Cahill Center for Astronomy and Astrophysics, California Institute of Technology, USA), M. Pasanen(Tuorla Observatory, University of Turku, Finland), A. B. Pushkarev(Pulkovo Observatory, St. Petersburg, Russia), A. C. S. Readhead(Cahill Center for Astronomy and Astrophysics, California Institute of Technology, USA), J. L. Richards(Department of Physics, Purdue University, USA), J. Sainio(Tuorla Observatory, University of Turku, Finland), D. N. Shakhovskoy(Crimean Astrophysical Observatory, Ukraine), K. V. Sokolovsky(Astro Space Center of Lebedev Physical Institute, 117997 Moscow, Russia), M. Tornikoski(Aalto University Metsähovi Radio Observatory, Finland), J. Tueller(Astrophysics Science Division, NASA Goddard Space Flight Center, USA), M. Weidinger(Theoretische Physik IV, Ruhr-Universität Bochum, Germany), J. Wilms(Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, Germany), Anne Lähteenmäki Group, Aalto-yliopisto, Aalto University, Institut de Física d’Altes Energies [Barcelone] (IFAE), Universitat Autònoma de Barcelona (UAB), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Instituto de Fisica Corpuscular (IFIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universitat de València (UV), Politecnico di Milano [Milan] (POLIMI), Universitá degli Studi dell’Insubria, Technische Universität Dortmund [Dortmund] (TU), IEEC-CSIC, Departamento de Ecología e Hidrología, Universidad de Murcia, Deutsches Elektronen-Synchrotron [Zeuthen] (DESY), Helmholtz-Gemeinschaft = Helmholtz Association, Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire d'études dynamiques et structurales de la sélectivité (LEDSS), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Département de Physique des Particules (ex SPP) (DPP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Departament d'Astronomia i Meteorologia [Barcelona] (DAM), Universitat de Barcelona (UB), Universita degli Studi di Padova, Universidad de Cantabria [Santander], Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Istituto Nazionale di Fisica Nucleare (INFN), Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) (MPI-P), Instituto de Biotecnología, Departamento de Biología Molecular de Plantas, UNAM, Institute for Physical Research (IPR), National Academy of Sciences of the Republic of Armenia [Yerevan] (NAS RA), Netherlands Institute for Radio Astronomy (ASTRON), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), 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)-Université Pierre et Marie Curie - Paris 6 (UPMC), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), INAF-Cagliari Astronomical Observatory, Instituto de Física Teórica UAM/CSIC (IFT), Universidad Autonoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dept. of Physics, Institut de Ciencies del Cosmos (ICCUB), Kao Group, Centre de Recherches sur les Macromolécules Végétales (CERMAV), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Optoelectronic Research Centre, University of Southampton, Department of Chemistry, Oulu, INAF - Osservatorio Astronomico di Brera (OAB), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Università degli Studi di Udine - University of Udine [Italie], Universita degli studi di Napoli 'Parthenope' [Napoli], Istituto di Astrofisica Spaziale e Fisica cosmica - Palermo (IASF-Pa), Vecteurs - Infections tropicales et méditerranéennes (VITROME), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut de Recherche Biomédicale des Armées (IRBA), Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), DAAA, ONERA, Université Paris Saclay (COmUE) [Meudon], ONERA-Université Paris-Saclay, University of Bath [Bath], Waves and Solitons LLC, 918 W. Windsong Dr., Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), J., Aleksić, L. A., Antonelli, P., Antoranz, M., Asensio, M., Backe, U., Barres de Almeida, J. A., Barrio, W., Bednarek, K., Berger, E., Bernardini, A., Biland, O., Blanch, R. K., Bock, A., Boller, S., Bonnefoy, G., Bonnoli, D., Borla Tridon, T., Bretz, E., Carmona, A., Carosi, D., Carreto Fidalgo, P., Colin, E., Colombo, J. L., Contrera, J., Cortina, L., Cossio, S., Covino, P., Da Vela, F., Dazzi, A., De Angeli, G., De Caneva, B., De Lotto, C., Delgado Mendez, M., Doert, A., Domínguez, D., Dominis Prester, D., Dorner, M., Doro, D., Eisenacher, D., Elsaesser, D., Ferenc, M. V., Fonseca, L., Font, C., Fruck, R. J., García López, M., Garczarczyk, D., Garrido Terrat, M., Gaug, G., Giavitto, N., Godinović, A., González Muñoz, S. R., Gozzini, A., Hadamek, D., Hadasch, A., Herrero, J., Hose, D., Hrupec, F., Jankowski, V., Kadeniu, S., Klepser, M. L., Knoetig, T., Krähenbühl, J., Krause, J., Kushida, A., La Barbera, D., Lela, E., Leonardo, N., Lewandowska, E., Lindfor, S., Lombardi, M., López, R., López Coto, A., López Orama, E., Lorenz, I., Lozano, M., Makariev, K., Mallot, G., Maneva, N., Mankuzhiyil, K., Mannheim, L., Maraschi, B., Marcote, M., Mariotti, M., Martínez, J., Masbou, D., Mazin, M., Meucci, J. M., Miranda, R., Mirzoyan, J., Moldón, A., Moralejo, P., Munar Adrover, D., Nakajima, A., Niedzwiecki, D., Nieto, K., Nilsson, N., Nowak, R., Orito, S., Paiano, M., Palatiello, D., Paneque, R., Paoletti, J. M., Parede, S., Partini, M., Persic, M., Pilia, F., Prada, P. G., Prada Moroni, E., Prandini, I., Puljak, I., Reichardt, R., Reinthal, W., Rhode, M., Ribó, J., Rico, S., Rügamer, A., Saggion, K., Saito, T. Y., Saito, M., Salvati, K., Satalecka, V., Scalzotto, V., Scapin, C., Schultz, T., Schweizer, S. N., Shore, A., Sillanpää, J., Sitarek, I., Snidaric, D., Sobczynska, F., Spanier, S., Spiro, V., Stamatescu, A., Stamerra, B., Steinke, J., Storz, S., Sun, T., Surić, L., Takalo, H., Takami, F., Tavecchio, P., Temnikov, T., Terzić, D., Tescaro, M., Teshima, O., Tibolla, D. F., Torre, T., Toyama, A., Treve, M., Uellenbeck, P., Vogler, R. M., Wagner, Q., Weitzel, F., Zandanel, R., Zanin, Longo, Francesco, F., Lucarelli, C., Pittori, S., Vercellone, D., Bastieri, C., Sbarra, E., Angelaki, L., Fuhrmann, I., Nestora, T. P., Krichbaum, A., Siever, J. A., Zensu, K. A., Antonyuk, W., Baumgartner, A., Berduygin, M., Carini, K., Cook, N., Gehrel, M., Kadler, Kovalev, Y. u. A., Y. Y., Kovalev, F., Krau, H. A., Krimm, A., Lähteenmäki, M. L., Lister, W., Max Moerbeck, M., Pasanen, A. B., Pushkarev, A. C. S., Readhead, J. L., Richard, J., Sainio, D. N., Shakhovskoy, K. V., Sokolovsky, M., Tornikoski, J., Tueller, M., Weidinger, J., Wilms, UAM. Departamento de Física Teórica, Universitá degli Studi dell’Insubria = University of Insubria [Varese] (Uninsubria), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Département de Physique des Particules (ex SPP) (DPhP), Università degli Studi di Padova = University of Padua (Unipd), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), 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)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut de Recherche Biomédicale des Armées [Brétigny-sur-Orge] (IRBA), Universitat Autònoma de Barcelona [Barcelona] (UAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Universitat de València (UV), Helmholtz-Gemeinschaft, National Institute for Nuclear Physics (INFN), National Academy of Sciences of Armenia, The Netherlands Institute for Radio Astronomy (ASTRON), 7990-AA Dwingeloo, Netherlands, Universidad Autonoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), INAF-OAB, and DAAA, ONERA, Université Paris Saclay [Meudon]

Subjects
galaxies [Gamma rays], Radiation mechanisms: non-thermal, Flux, Astrophysics, 01 natural sciences, LARGE-AREA TELESCOPE, law.invention, law, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], BL Lacertae objects: individual: 1ES 2344+514, MAGIC (telescope), 010303 astronomy & astrophysics, galaxies: active, BL Lacerae objects: individual: 1ES 2344+514, gamma rays: galaxies, X-rays: individuals: 1ES 2344+514, radiation mechanisms: non-thermal, ComputingMilieux_MISCELLANEOUS, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, ACTIVE GALACTIC NUCLEI, BL-LACERTAE OBJECTS, GAMMA-RAY EMISSION, SIMULTANEOUS MULTIWAVELENGTH OBSERVATIONS, SELF-COMPTON MODEL, X-RAY, LAC OBJECTS, RELATIVISTIC JETS, MARKARIAN 501, Gamma ray, non-thermal [radiation mechanisms], active [galaxies], astro-ph.CO, Spectral energy distribution, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Flare, Astrophysics - Cosmology and Nongalactic Astrophysics, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Cosmology and Nongalactic Astrophysics (astro-ph.CO), [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astrophysics::High Energy Astrophysical Phenomena, education, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, galaxie [gamma rays], 010308 nuclear & particles physics, Física, Astronomy and Astrophysics, Light curve, individual: 1ES 2344+514 [BL Lacertae objects], [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], galaxies [gamma-rays], Space and Planetary Science, ddc:520, individuals: 1ES 2344+514 [X-rays], Fermi Gamma-ray Space Telescope
Abstract

Astronomy and Astrophysics 556 (2013): A67 reproduced with permission from Astronomy and Astrophysics, Context. BL Lacertae objects are variable at all energy bands on time scales down to minutes. To construct and interpret their spectral energy distribution (SED), simultaneous broad-band observations are mandatory. Up to now, the number of objects studied during such campaigns is very limited and biased towards high flux states. Aims.We present the results of a dedicated multi-wavelength study of the high-frequency peaked BL Lacertae (HBL) object and known TeV emitter 1ES 2344+514 by means of a pre-organised campaign. Methods.The observations were conducted during simultaneous visibility windows of MAGIC and AGILE in late 2008. The measurements were complemented by Metsähovi, RATAN-600, KVA+Tuorla, Swift and VLBA pointings. Additional coverage was provided by the ongoing long-term F-GAMMA and MOJAVE programs, the OVRO 40-m and CrAO telescopes as well as the Fermi satellite. The obtained SEDs are modelled using a one-zone as well as a self-consistent two-zone synchrotron self-Compton model. Results. 1ES 2344+514 was found at very low flux states in both X-rays and very high energy gamma rays. Variability was detected in the low frequency radio and X-ray bands only, where for the latter a small flare was observed. The X-ray flare was possibly caused by shock acceleration characterised by similar cooling and acceleration time scales. MOJAVE VLBA monitoring reveals a static jet whose components are stable over time scales of eleven years, contrary to previous findings. There appears to be no significant correlation between the 15 GHz and R-band monitoring light curves. The observations presented here constitute the first multi-wavelength campaign on 1ES 2344+514 from radio to VHE energies and one of the few simultaneous SEDs during low activity states. The quasi-simultaneous Fermi-LAT data poses some challenges for SED modelling, but in general the SEDs are described well by both applied models. The resulting parameters are typical for TeV emitting HBLs. Consequently it remains unclear whether a so-called quiescent state was found in this campaign, The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant 127740 of the Academy of Finland, by the DFG Cluster of Excellence “Origin and Structure of the Universe”, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0. The AGILE Mission is funded by the Italian Space Agency (ASI), with scientific and programmatic participation by the Italian Institute of Astrophysics (INAF) and the Italian Institute of Nuclear Physics (INFN). Research partially supported through the ASI grants no. I/089/06/2 and I/042/10/0. The Fermi-LAT Collaboration acknowledges support from a number of agencies and institutes for both development and the operation of the LAT as well as scientific data analysis. These include NASA and DOE in the United States, CEA/Irfu and IN2P3/CNRS in France, ASI and INFN in Italy, MEXT, KEK, and JAXA in Japan, and the K. A.Wallenberg Foundation, the Swedish Research Council and the National Space Board in Sweden. Additional support from INAF in Italy and CNES in France for science analysis during the operations phase is also gratefully acknowledged

Published
2013

29. Multiwavelength observations of Mrk 501 in 2008

Author

MAGIC Collaboration, J. Aleksić(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), S. Ansoldi(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), L. A. Antonelli(INAF National Institute for Astrophysics, I-00136 Rome, Italy), P. Antoranz(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), A. Babic(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), P. Bangale(Max-Planck-Institut für Physik, D-80805 München, Germany), U. Barres de Almeida(Max-Planck-Institut für Physik, D-80805 München, Germany), J. A. Barrio(Universidad Complutense, E-28040 Madrid, Spain), J. Becerra González(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), W. Bednarek(University of Lodz, PL-90236 Lodz, Poland), K. Berger(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), E. Bernardini(Deutsches Elektronen-Synchrotron), A. Biland(ETH Zurich, CH-8093 Zurich, Switzerland), O. Blanch(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), R. K. Bock(Max-Planck-Institut für Physik, D-80805 München, Germany), S. Bonnefoy(Universidad Complutense, E-28040 Madrid, Spain), G. Bonnoli(INAF National Institute for Astrophysics, I-00136 Rome, Italy), F. Borracci(Max-Planck-Institut für Physik, D-80805 München, Germany), T. Bretz(Universität Würzburg, D-97074 Würzburg, Germany), E. Carmona(Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, E-28040 Madrid, Spain), A. Carosi(INAF National Institute for Astrophysics, I-00136 Rome, Italy), D. Carreto Fidalgo(Universität Würzburg, D-97074 Würzburg, Germany), P. Colin(Max-Planck-Institut für Physik, D-80805 München, Germany), E. Colombo(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), J. L. Contreras(Universidad Complutense, E-28040 Madrid, Spain), J. Cortina(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), S. Covino(INAF National Institute for Astrophysics, I-00136 Rome, Italy), P. Da Vela(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), F. Dazzi(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), A. De Angelis(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), G. De Caneva(Deutsches Elektronen-Synchrotron), B. De Lotto(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), C. Delgado Mendez(Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, E-28040 Madrid, Spain), M. Doert(Technische Universität Dortmund, D-44221 Dortmund, Germany), A. Domínguez(Inst. de Astrofísica de Andalucía), D. Dominis Prester(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), D. Dorner(Universität Würzburg, D-97074 Würzburg, Germany), M. Doro(Università di Padova and INFN, I-35131 Padova, Italy), S. Einecke(Technische Universität Dortmund, D-44221 Dortmund, Germany), D. Eisenacher(Universität Würzburg, D-97074 Würzburg, Germany), D. Elsaesser(Universität Würzburg, D-97074 Würzburg, Germany), E. Farina(Università dell'Insubria, Como, I-22100 Como, Italy), D. Ferenc(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), M. V. Fonseca(Universidad Complutense, E-28040 Madrid, Spain), L. Font(Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain), K. Frantzen(Technische Universität Dortmund, D-44221 Dortmund, Germany), C. Fruck(Max-Planck-Institut für Physik, D-80805 München, Germany), R. J. García López(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), M. Garczarczyk(Deutsches Elektronen-Synchrotron), D. Garrido Terrats(Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain), M. Gaug(Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain), G. Giavitto(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), N. Godinović(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), A. González Muñoz(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), S. R. Gozzini(Deutsches Elektronen-Synchrotron), A. Hadamek(Technische Universität Dortmund, D-44221 Dortmund, Germany), D. Hadasch(Institut de Ciències de l'Espai), A. Herrero(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), D. Hildebrand(ETH Zurich, CH-8093 Zurich, Switzerland), J. Hose(Max-Planck-Institut für Physik, D-80805 München, Germany), D. Hrupec(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), W. Idec(University of Lodz, PL-90236 Lodz, Poland), V. Kadenius(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), H. Kellermann(Max-Planck-Institut für Physik, D-80805 München, Germany), M. L. Knoetig(ETH Zurich, CH-8093 Zurich, Switzerland), J. Krause(Max-Planck-Institut für Physik, D-80805 München, Germany), J. Kushida(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), A. La Barbera(INAF National Institute for Astrophysics, I-00136 Rome, Italy), D. Lelas(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), N. Lewandowska(Universität Würzburg, D-97074 Würzburg, Germany), E. Lindfors(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), S. Lombardi(INAF National Institute for Astrophysics, I-00136 Rome, Italy), M. López(Universidad Complutense, E-28040 Madrid, Spain), R. López-Coto(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), A. López-Oramas(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), E. Lorenz(Max-Planck-Institut für Physik, D-80805 München, Germany), I. Lozano(Universidad Complutense, E-28040 Madrid, Spain), M. Makariev(Inst. for Nucl. Research and Nucl. Energy, BG-1784 Sofia, Bulgaria), K. Mallot(Deutsches Elektronen-Synchrotron), G. Maneva(Inst. for Nucl. Research and Nucl. Energy, BG-1784 Sofia, Bulgaria), N. Mankuzhiyil(2,*), K. Mannheim(Universität Würzburg, D-97074 Würzburg, Germany), L. Maraschi(INAF National Institute for Astrophysics, I-00136 Rome, Italy), B. Marcote(Universitat de Barcelona), M. Mariotti(Università di Padova and INFN, I-35131 Padova, Italy), M. Martínez(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), D. Mazin(Max-Planck-Institut für Physik, D-80805 München, Germany), U. Menzel(Max-Planck-Institut für Physik, D-80805 München, Germany), M. Meucci(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), J. M. Miranda(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), R. Mirzoyan(Max-Planck-Institut für Physik, D-80805 München, Germany), A. Moralejo(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), P. Munar-Adrover(Universitat de Barcelona), D. Nakajima(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), A. Niedzwiecki(University of Lodz, PL-90236 Lodz, Poland), K. Nilsson(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), N. Nowak(Max-Planck-Institut für Physik, D-80805 München, Germany), R. Orito(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), A. Overkemping(Technische Universität Dortmund, D-44221 Dortmund, Germany), S. Paiano(Università di Padova and INFN, I-35131 Padova, Italy), M. Palatiello(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), D. Paneque(6,*), R. Paoletti(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), J. M. Paredes(Universitat de Barcelona), X. Paredes-Fortuny(Universitat de Barcelona), S. Partini(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), M. Persic(Università di Udine, and INFN Trieste, I-33100 Udine, Italy), F. Prada(Inst. de Astrofísica de Andalucía), P. G. Prada Moroni(Università di Pisa, and INFN Pisa, I-56126 Pisa, Italy), E. Prandini(Università di Padova and INFN, I-35131 Padova, Italy), S. Preziuso(Università di Siena, and INFN Pisa, I-53100 Siena, Italy), I. Puljak(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), R. Reinthal(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), W. Rhode(Technische Universität Dortmund, D-44221 Dortmund, Germany), M. Ribó(Universitat de Barcelona), J. Rico(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), J. Rodriguez Garcia(Max-Planck-Institut für Physik, D-80805 München, Germany), S. Rügamer(Universität Würzburg, D-97074 Würzburg, Germany), A. Saggion(Università di Padova and INFN, I-35131 Padova, Italy), T. Saito(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), K. Saito(Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Japan), M. Salvati(INAF National Institute for Astrophysics, I-00136 Rome, Italy), K. Satalecka(7,*), V. Scalzotto(Università di Padova and INFN, I-35131 Padova, Italy), V. Scapin(Universidad Complutense, E-28040 Madrid, Spain), C. Schultz(Università di Padova and INFN, I-35131 Padova, Italy), T. Schweizer(Max-Planck-Institut für Physik, D-80805 München, Germany), S. N. Shore(Università di Pisa, and INFN Pisa, I-56126 Pisa, Italy), A. Sillanpää(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), J. Sitarek(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), I. Snidaric(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), D. Sobczynska(University of Lodz, PL-90236 Lodz, Poland), F. Spanier(Universität Würzburg, D-97074 Würzburg, Germany), V. Stamatescu(IFAE, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain), A. Stamerra(INAF National Institute for Astrophysics, I-00136 Rome, Italy), T. Steinbring(Universität Würzburg, D-97074 Würzburg, Germany), J. Storz(Universität Würzburg, D-97074 Würzburg, Germany), S. Sun(Max-Planck-Institut für Physik, D-80805 München, Germany), T. Surić(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), L. Takalo(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), F. Tavecchio(INAF National Institute for Astrophysics, I-00136 Rome, Italy), P. Temnikov(Inst. for Nucl. Research and Nucl. Energy, BG-1784 Sofia, Bulgaria), T. Terzić(Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, HR-10000 Zagreb, Croatia), D. Tescaro(Inst. de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain), M. Teshima(Max-Planck-Institut für Physik, D-80805 München, Germany), J. Thaele(Technische Universität Dortmund, D-44221 Dortmund, Germany), O. Tibolla(Universität Würzburg, D-97074 Würzburg, Germany), D. F. Torres(Institut de Ciències de l'Espai), T. Toyama(Max-Planck-Institut für Physik, D-80805 München, Germany), A. Treves(Università dell'Insubria, Como, I-22100 Como, Italy), M. Uellenbeck(Technische Universität Dortmund, D-44221 Dortmund, Germany), P. Vogler(ETH Zurich, CH-8093 Zurich, Switzerland), R. M. Wagner(Max-Planck-Institut für Physik, D-80805 München, Germany), F. Zandanel(Inst. de Astrofísica de Andalucía), R. Zanin(Universitat de Barcelona), VERITAS Collaboration(Deutsches Elektronen-Synchrotron), (Deutsches Elektronen-Synchrotron), B. Behera(Deutsches Elektronen-Synchrotron), M. Beilicke(Department of Physics, Washington University, St. Louis, MO 63130, USA), W. Benbow(Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645, USA), R. Bird(School of Physics, University College Dublin, Belfield, Dublin 4, Ireland), A. Bouvier(Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064, USA), V. Bugaev(Department of Physics, Washington University, St. Louis, MO 63130, USA), M. Cerruti(Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645, USA), X. Chen(Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany), L. Ciupik(Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605, USA), E. Collins-Hughes(School of Physics, University College Dublin, Belfield, Dublin 4, Ireland), W. Cui(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), C. Duke(Department of Physics, Grinnell College, Grinnell, IA 50112-1690, USA), J. Dumm(School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA), A. Falcone(Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802, USA), S. Federici(now at GRAPPA Institute, University of Amsterdam, 1098XH), Q. Feng(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), J. P. Finley(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), L. Fortson(School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA), A. Furniss(Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064, USA), N. Galante(Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645, USA), G. H. Gillanders(School of Physics, National University of Ireland Galway, University Road, Galway, Ireland), S. Griffin(Physics Department, McGill University, Montreal, QC H3A 2T8, Canada), S. T. Griffiths(Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242, USA), J. Grube(Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605, USA), G. Gyuk(Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605, USA), D. Hanna(Physics Department, McGill University, Montreal, QC H3A 2T8, Canada), J. Holder(Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716, USA), C. A. Johnson(Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064, USA), P. Kaaret(Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242, USA), M. Kertzman(Department of Physics and Astronomy, DePauw University, Greencastle, IN 46135-0037, USA), D. Kieda(Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA), H. Krawczynski(Department of Physics, Washington University, St. Louis, MO 63130, USA), M. J. Lang(School of Physics, National University of Ireland Galway, University Road, Galway, Ireland), A. S Madhavan(Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA), G. Maier(Deutsches Elektronen-Synchrotron), P. Majumdar(Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA), K. Meagher(School of Physics and Center for Relativistic Astrophysics, Georgia Institute of Technology, 837 State Street NW, Atlanta, GA 30332-0430), P. Moriarty(Department of Life and Physical Sciences, Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland), R. Mukherjee(Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027, USA), D. Nieto(Physics Department, Columbia University, New York, NY 10027, USA), A. O'Faoláin de Bhróithe(School of Physics, University College Dublin, Belfield, Dublin 4, Ireland), R. A. Ong(Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA), A. N. Otte(School of Physics and Center for Relativistic Astrophysics, Georgia Institute of Technology, 837 State Street NW, Atlanta, GA 30332-0430), A. Pichel(Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67 - Sucursal 28), M. Pohl(Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany), A. Popkow(Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA), H. Prokoph(Deutsches Elektronen-Synchrotron), J. Quinn(School of Physics, University College Dublin, Belfield, Dublin 4, Ireland), J. Rajotte(Physics Department, McGill University, Montreal, QC H3A 2T8, Canada), G. Ratliff(Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605, USA), L. C. Reyes(Physics Department, California Polytechnic State University, San Luis Obispo, CA 94307, USA), P. T. Reynolds(Department of Applied Physics and Instrumentation, Cork Institute of Technology, Bishopstown, Cork, Ireland), G. T. Richards(School of Physics and Center for Relativistic Astrophysics, Georgia Institute of Technology, 837 State Street NW, Atlanta, GA 30332-0430), E. Roache(Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645, USA), G. H. Sembroski(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), K. Shahinyan(School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA), F. Sheidaei(Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA), A. W. Smith(Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA), D. Staszak(Physics Department, McGill University, Montreal, QC H3A 2T8, Canada), I. Telezhinsky(Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany), M. Theiling(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), J. Tyler(Physics Department, McGill University, Montreal, QC H3A 2T8, Canada), A. Varlotta(Department of Physics, Purdue University, West Lafayette, IN 47907, USA), S. Vincent(Deutsches Elektronen-Synchrotron), S. P. Wakely(Enrico Fermi Institute, University of Chicago, Chicago, IL 60637, USA), T. C. Weekes(Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645, USA), R. Welsing(Deutsches Elektronen-Synchrotron), D. A. Williams(Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064, USA), A. Zajczyk(Department of Physics, Washington University, St. Louis, MO 63130, USA), B. Zitzer(Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA), External Collaborators(INAF, Osservatorio Astronomico di Torino, I-10025 Pino Torinese), (INAF, Osservatorio Astronomico di Torino, I-10025 Pino Torinese), M. Villata(INAF, Osservatorio Astronomico di Torino, I-10025 Pino Torinese), C. M. Raiteri(INAF, Osservatorio Astronomico di Torino, I-10025 Pino Torinese), M. Ajello(Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450, USA), M. Perri(ASI-Science Data Center, Via del Politecnico, I-00133 Rome, Italy), H. D. Aller(Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1042, USA), M. F. Aller(Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1042, USA), V. M. Larionov(Astron. Inst., St.-Petersburg State Univ., Russia), N. V. Efimova(Astron. Inst., St.-Petersburg State Univ., Russia), T. S. Konstantinova(Astron. Inst., St.-Petersburg State Univ., Russia), E. N. Kopatskaya(Astron. Inst., St.-Petersburg State Univ., Russia), W. P. Chen(Graduate Institute of Astronomy, National Central University, 300 Jhongda Rd., Jhongli 32001, Taiwan), E. Koptelova(Graduate Institute of Astronomy, National Central University, 300 Jhongda Rd., Jhongli 32001, Taiwan), H. Y. Hsiao(Graduate Institute of Astronomy, National Central University, 300 Jhongda Rd., Jhongli 32001, Taiwan), O. M. Kurtanidze(Abastumani Observatory, Mt. Kanobili, 0301 Abastumani, Georgia), M. G. Nikolashvili(Abastumani Observatory, Mt. Kanobili, 0301 Abastumani, Georgia), G. N. Kimeridze(Abastumani Observatory, Mt. Kanobili, 0301 Abastumani, Georgia), B. Jordan(School of Cosmic Physics, Dublin Institute For Advanced Studies, Ireland), P. Leto(INAF - Osservatorio Astrofisico di Catania, Italy), C. S. Buemi(INAF - Osservatorio Astrofisico di Catania, Italy), C. Trigilio(INAF - Osservatorio Astrofisico di Catania, Italy), G. Umana(INAF - Osservatorio Astrofisico di Catania, Italy), A. Lahtenmaki(Aalto University Metsähovi Radio Observatory Metsähovintie 114 FIN-02540 Kylmälä Finland), E. Nieppola(Aalto University Metsähovi Radio Observatory Metsähovintie 114 FIN-02540 Kylmälä Finland), M. Tornikoski(Aalto University Metsähovi Radio Observatory Metsähovintie 114 FIN-02540 Kylmälä Finland), J. Sainio(Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, Finland), M. Giroletti(INAF Istituto di Radioastronomia, 40129 Bologna, Italy), A. Cesarini(University of Trento, Department of Physics, I38050 Povo, Trento, Italy), L. Fuhrmann(Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany), Yu. A. Kovalev(Astro Space Center of the Lebedev Physical Institute, 117997), Y. Y. Kovalev(Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany), Anne Lähteenmäki Group, Department of Radio Science and Engineering, Aalto-yliopisto, Aalto University, Universitat de Barcelona, School services, ELEC, and ~

Subjects
extragalactic background light, Ciencias Físicas, Flux, Electron, Astrophysics, 7. Clean energy, law.invention, purl.org/becyt/ford/1 [https], Raigs gamma, bl lacertae objects, law, individual: Mrk 501 [BL Lacertae objects], Physics, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, 213 Electronic, automation and communications engineering, electronics, Astroparticle physics, BL Lacertae objects: individual: Mrk 501, Gamma rays: general, Astronomy and Astrophysics, Space and Planetary Science, Synchrotron, individual: Mrk 50 [BL Lacertae objects], Homogeneous, astroparticle physics, Spectral energy distribution, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, CIENCIAS NATURALES Y EXACTAS, 1171 Geosciences, Astrophysics::High Energy Astrophysical Phenomena, emitting electrons, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 114 Physical sciences, bl lacertae objects: individual: mrk 501, crab-nebula, Blazar, Astrophysics::Galaxy Astrophysics, tev blazars, variability, 221 Nanotechnology, Gamma rays, Individual: Mrk 501, Institut für Physik und Astronomie, purl.org/becyt/ford/1.3 [https], gamma rays: general, Galaxies, gamma-ray emission, telescope system, Galàxies, Active Galaxies, blazars, gamma-rays, Mrk 501, Astronomía, Crab Nebula, x-ray, 115 Astronomy and space science, Low emission, 216 Materials engineering, Galàxies actives, active galactic nuclei, Active galaxies, ddc:520, general [gamma rays]
Abstract

Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. Our goal is to characterize in detail the source gamma-ray emission, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. We organized a multiwavelength (MW) campaign on Mrk 501 between March and May 2008. This multi-instrument effort included the most sensitive VHE gamma-ray instruments in the northern hemisphere, namely the imaging atmospheric Cherenkov telescopes MAGIC and VERITAS, as well as Swift, RXTE, the F-GAMMA, GASP-WEBT, and other collaborations and instruments. Mrk 501 was found to be in a low state of activity during the campaign, with a VHE flux in the range of 10%-20% of the Crab nebula flux. Nevertheless, significant flux variations were detected with various instruments, with a trend of increasing variability with energy. The broadband spectral energy distribution during the two different emission states of the campaign can be adequately described within the homogeneous one-zone synchrotron self-Compton model, with the (slightly) higher state described by an increase in the electron number density. This agrees with previous studies of the broadband emission of this source during flaring and non-flaring states. We report for the first time a tentative X-ray-to-VHE correlation during a low VHE activity. Although marginally significant, this positive correlation between X-ray and VHE, which has been reported many times during flaring activity, suggests that the mechanisms that dominate the X-ray/VHE emission during non-flaring-activity are not substantially different from those that are responsible for the emission during flaring activity., Comment: Accepted for publication in A&A

Published
2015

30. Single-epoch VLBI imaging study of bright active galactic nuclei at 2 and 8 GHz

Author

Y. Y. Kovalev and A. B. Pushkarev

Subjects
Physics, Brightness, Spectral index, Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radio spectrum, Space and Planetary Science, Brightness temperature, Very-long-baseline interferometry, Very Long Baseline Array, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Fermi Gamma-ray Space Telescope
Abstract

We investigate statistical and individual astrophysical properties of active galactic nuclei (AGNs), such as parsec-scale flux density, core dominance, angular and linear sizes, maximum observed brightness temperatures of VLBI core components, spectral index distributions for core and jet components, and evolution of brightness temperature along the jets. Furthermore, we statistically compare core flux densities and brightness temperature as well as jet spectral indices of gamma-ray bright and weak sources. We used 19 very long baseline interferometry (VLBI) observing sessions carried out simultaneously at 2.3 and 8.6 GHz with the participation of 10 Very Long Baseline Array (VLBA) stations and up to 10 additional geodetic telescopes. The observations span the period 1998-2003. We present here single-epoch results from high-resolution radio observations of 370 AGNs. Our VLBI images at 2.3 and 8.6 GHz as well as Gaussian models are presented and analyzed. At least one-fourth of the cores are completely unresolved on the longest baselines of the global VLBI observations. The VLBI core components are partially opaque with the median value of spectral index of alpha_core=0.3, while the jet features are usually optically thin alpha_jet=-0.7. The spectral index typically decreases along the jet ridge line owing to the spectral aging, with a median value of -0.05 mas^-1. Brightness temperatures are found to be affected by Doppler boosting and reaching up to \sim10^13 K with a median of \sim2.5x10^11 K at both frequencies. The brightness temperature gradients along the jets typically follow a power law T_b\simr^-2.2 at both frequencies. 147 sources (40%) positionally associated with gamma-ray detections from the Fermi LAT Second Source Catalog have higher core flux densities and brightness temperatures, and are characterized by the less steep radio spectrum of the optically thin jet emission., Comment: 15 pages, 21 figures, accepted by A&A on May 22, 2012, machine readable tables are available from the source of the paper

Published
2012
Full Text
View/download PDF

31. Multiwavelength observations of markarian 421 in 2005-2006

Author

D. Horan, V. A. Acciari, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. L. Byrum, A. Cannon, O. Celik, A. Cesarini, Y. C. K. Chow, L. Ciupik, P. Cogan, A. D. Falcone, S. J. Fegan, J. P. Finley, P. Fortin, L. F. Fortson, D. Gall, G. H. Gillanders, J. Grube, G. Gyuk, D. Hanna, E. Hays, M. Kertzman, J. Kildea, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, K. Lee, P. Moriarty, T. Nagai, J. Niemiec, R. A. Ong, J. S. Perkins, M. Pohl, J. Quinn, P. T. Reynolds, H. J. Rose, G. H. Sembroski, A. W. Smith, D. Steele, S. P. Swordy, J. A. Toner, V. V. Vassiliev, S. P. Wakely, T. C. Weekes, R. J. White, D. A. Williams, M. D. Wood, B. Zitzer, H. D. Aller, M. F. Aller, M. Baker, D. Barnaby, M. T. Carini, P. Charlot, J. P. Dumm, N. E. Fields, T. Hovatta, B. Jordan, Y. A. Kovalev, Y. Y. Kovalev, H. A. Krimm, O. M. Kurtanidze, A. Lähteenmäki, J. F. Le Campion, J. Maune, T. Montaruli, A. C. Sadun, S. Smith, M. Tornikoski, M. Turunen, and R. Walters

Subjects
spectral slope variability, bl-lacertae objects, FOS: Physical sciences, bl lacertae objects: individual (markarian 421), proton blazar, tev blazar markarian-421, Astrophysics, timing explorer, Radio spectrum, law.invention, Telescope, Observatory, law, Blazar, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Northern Hemisphere, Astronomy and Astrophysics, gamma-ray emission, lac objects, Wavelength, x-ray, Space and Planetary Science, correlated variability, active galactic nuclei, Spectral energy distribution, Astrophysics - High Energy Astrophysical Phenomena, gamma rays: observations, x-rays: individual (markarian 421)
Abstract

Since September 2005, the Whipple 10m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five Northern Hemisphere blazars that have already been detected at the Whipple Observatory, Markarian 421, H1426+428, Markarian 501, 1ES 1959+650 and 1ES 2344+514, are monitored routinely each night that they are visible. We report on the Markarian 421 observations taken from November 2005 to June 2006 in the gamma-ray, X-ray, optical and radio bands. During this time, Markarian 421 was found to be variable at all wavelengths probed. Both the variability and the correlations among different energy regimes are studied in detail here. A tentative correlation, with large spread, was measured between the X-ray and gamma-ray bands, while no clear correlation was evident among the other energy bands. In addition to this, the well-sampled spectral energy distribution of Markarian 421 (1101+384) is presented for three different activity levels. The observations of the other blazar targets will be reported separately., Comment: 58 pages, 22 Figures. Accepted for publication in ApJ

Published
2009

32. Fermi Discovery of Gamma-Ray Emission from NGC 1275

Author

A. A. Abdo, M. Ackermann, M. Ajello, K. Asano, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Celotti, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Colafrancesco, L. R. Cominsky, J. Conrad, L. Costamante, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, D. Donato, E. do Couto e Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, J. Finke, W. B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, M. Georganopoulos, S. Germani, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, I. A. Grenier, M.-H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, M. Kadler, T. Kamae, Y. Kanai, H. Katagiri, J. Kataoka, N. Kawai, M. Kerr, J. Knödlseder, F. Kuehn, M. Kuss, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F.-W. Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, R. Sato, P. M. Saz Parkinson, C. Sgrò, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J.-L. Starck, M. S. Strickman, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, G. B. Taylor, J. G. Thayer, D. J. Thompson, D. F. Torres, G. Tosti, Y. Uchiyama, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, K. S. Wood, T. Ylinen, M. Ziegler, H. D. Aller, M. F. Aller, K. I. Kellermann, Y. Y. Kovalev, Yu. A. Kovalev, M. L. Lister, A. B. Pushkarev, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Fermi-LAT, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), Observatoire Midi-Pyrénées (OMP), 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Abdo, A. A., Ackermann, M., Ajello, M., Asano, K., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Caliandro, G. A., Cameron, R. A., Caraveo, A., Casandjian, J. M., Cavazzuti, E., Cecchi, C., Celotti, A., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen Tanugi, J., Colafrancesco, S., Cominsky, L. R., Conrad, J., Costamante, L., Dermer, C. D., Angelis, A. d., Palma, F. d., Digel, S. W., Donato, D., Silva, E. D. E., Drell, P. S., Dubois, R., Dumora, D., Farnier, C., Favuzzi, C., Finke, J., Focke, W. B., Frailis, M., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Georganopoulos, M., Germani, S., Giebels, B., Giglietto, N., Giordano, F., Glanzman, T., Grenier, I. A., Grondin, M. H., Grove, J. E., Guillemot, L., Guiriec, S., Hanabata, Y., Harding, A. K., Hartman, R. C., Hayashida, M., Hays, E., Hughes, R. E., Johannesson, G., Johnson, A. S., Johnson, R. P., Johnson, W. N., Kadler, M., Kamae, T., Kanai, Y., Katagiri, H., Kataoka, J., Kawai, N., Kerr, M., Knodlseder, J., Kuehn, F., Kuss, M., Latronico, L., Lemoine Goumard, M., Longo, Francesco, Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Makeev, A., Mazziotta, M. N., Mcenery, J. E., Meurer, C., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nakamori, T., Nolan, L., Norris, J. P., Nuss, E., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panetta, J. H., Parent, D., Pepe, M., Pesce Rollins, M., Piron, F., Porter, T. A., Raino, S., Razzano, M., Reimer, A., Reimer, O., Reposeur, T., Ritz, S., Rodriguez, A. Y., Romani, R. W., Ryde, F., Sadrozinski, H. F. W., Sambruna, R., Sanchez, D., Sander, A., Sato, R., Parkinson, P. M. S., Sgro, C., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Starck, J. L., Strickman, M. S., Strong, A. W., Suson, D. J., Tajima, H., Takahashi, H., Takahashi, T., Tanaka, T., Taylor, G. B., Thayer, J. G., Thompson, D. J., Torres, D. F., Tosti, G., Uchiyama, Y., Usher, T. L., Vilchez, N., Vitale, V., Waite, A. P., Wood, K. S., Ylinen, T., Ziegler, M., Aller, H. D., Aller, M. F., Kellermann, K. I., Kovalev, Y. Y., Kovalev, Y. A., Lister, M. L., and Pushkarev, A. B.

Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Cosmology and Nongalactic Astrophysics (astro-ph.CO), Radiation mechanisms: non-thermal, Point source, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Fermi satellite, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Gamma rays: observations, 01 natural sciences, High Energy Gamma-ray Astronomy, law.invention, Telescope, Galaxies: individual (NGC 1275), Settore FIS/05 - Astronomia e Astrofisica, law, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Galaxies: active, Galaxies: jets, 010308 nuclear & particles physics, Gamma ray, Center (category theory), galaxies: active, galaxies: individual: NGC 1275, galaxies: jets, gamma rays: observations, radiation mechanisms: non-thermal, Astronomy and Astrophysics, Galaxies, Galaxy, Space and Planetary Science, Elliptical galaxy, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Fermi Gamma-ray Space Telescope
Abstract

著者人数：170名, Accepted: 2009-04-20, 資料番号: SA1000972000

Published
2009

33. The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005

Author

M. Villata, C. M. Raiteri, V. M. Larionov, M. G. Nikolashvili, M. F. Aller, U. Bach, D. Carosati, F. Hroch, M. A. Ibrahimov, S. G. Jorstad, Y. Y. Kovalev, A. Lähteenmäki, K. Nilsson, H. Teräsranta, G. Tosti, H. D. Aller, A. A. Arkharov, A. Berdyugin, P. Boltwood, C. S. Buemi, R. Casas, P. Charlot, J. M. Coloma, A. Di Paola, G. Di Rico, G. N. Kimeridze, T. S. Konstantinova, E. N. Kopatskaya, Yu. A. Kovalev, O. M. Kurtanidze, L. Lanteri, E. G. Larionova, L. V. Larionova, J.-F. Le Campion, P. Leto, E. Lindfors, A. P. Marscher, K. Marshall, J. P. McFarland, I. M. McHardy, H. R. Miller, G. Nucciarelli, M. P. Osterman, M. Pasanen, T. Pursimo, J. A. Ros, A. C. Sadun, L. A. Sigua, L. Sixtova, L. O. Takalo, M. Tornikoski, C. Trigilio, G. Umana, G. Z. Xie, X. Zhang, S. B. Zhou, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Instituto de Neurociencias de Alicante, Universidad Miguel Hernández [Elche] (UMH), Dipartimento di Fisica e Geologia [Perugia], Università degli Studi di Perugia = University of Perugia (UNIPG), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Departamento de Bioquímica y Biología Molecular, Universitat de València (UV), Abteilung Klinische Sozialmedizin, Berufs- und Umweltdermatologie, Universität Heidelberg [Heidelberg] = Heidelberg University, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia (UNIPG), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Facultad de Farmacia, Universidad de Valencia, Valencia, Spain, Universität Heidelberg [Heidelberg], Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], galaxies: active, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, Telescope, law, 0103 physical sciences, BL+Lacertae<%2FASTROBJ>%22">galaxies: BL Lacertae objects: individual: BL Lacertae, Blazar, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, galaxies: BL Lacertae objects: individual: BL Lacertae, 010308 nuclear & particles physics, galaxies: BL Lacertae objects: general, galaxies: jets, galaxies: quasars: general, Radio flux, Astronomy and Astrophysics, Light curve, Space and Planetary Science, Correlation analysis, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Since 1997, BL Lacertae has undergone a phase of high optical activity, with the occurrence of several prominent outbursts. Starting from 1999, the Whole Earth Blazar Telescope (WEBT) consortium has organized various multifrequency campaigns on this blazar, collecting tens of thousands of data points. One of the main issues in the study of this huge dataset has been the search for correlations between the optical and radio flux variations, and for possible periodicities in the light curves. The analysis of the data assembled during the first four campaigns (comprising also archival data to cover the period 1968-2003) revealed a fair optical-radio correlation in 1994-2003, with a delay of the hard radio events of ~100 days. Moreover, various statistical methods suggested the existence of a radio periodicity of ~8 years. In 2004 the WEBT started a new campaign to extend the dataset to the most recent observing seasons, in order to possibly confirm and better understand the previous results. In this campaign we have collected and assembled about 11000 new optical observations from twenty telescopes, plus near-IR and radio data at various frequencies. Here, we perform a correlation analysis on the long-term R-band and radio light curves. In general, we confirm the ~100-day delay of the hard radio events with respect to the optical ones, even if longer (~200-300 days) time lags are also found in particular periods. The radio quasi-periodicity is confirmed too, but the "period" seems to progressively lengthen from 7.4 to 9.3 years in the last three cycles. The optical and radio behaviour in the last forty years suggests a scenario where geometric effects play a major role. In particular, the alternation of enhanced and suppressed optical activity (accompanied by hard and soft radio events, respectively) can, Comment: 6 pages, 4 figures

Published
2009
Full Text
View/download PDF

34. Results of WEBT, VLBA and RXTE monitoring of 3C 279 during 2006-2007

Author

V. M. Larionov, S. G. Jorstad, A. P. Marscher, C. M. Raiteri, M. Villata, I. Agudo, M. F. Aller, A. A. Arkharov, I. M. Asfandiyarov, U. Bach, R. Bachev, A. Berdyugin, M. Böttcher, C. S. Buemi, P. Calcidese, D. Carosati, P. Charlot, W.-P. Chen, A. Di Paola, M. Dolci, S. Dogru, V. T. Doroshenko, Yu. S. Efimov, A. Erdem, A. Frasca, L. Fuhrmann, P. Giommi, L. Glowienka, A. C. Gupta, M. A. Gurwell, V. A. Hagen-Thorn, W.-S. Hsiao, M. A. Ibrahimov, B. Jordan, M. Kamada, T. S. Konstantinova, E. N. Kopatskaya, Y. Y. Kovalev, Y. A. Kovalev, O. M. Kurtanidze, A. Lähteenmäki, L. Lanteri, L. V. Larionova, P. Leto, P. Le Campion, C.-U. Lee, E. Lindfors, E. Marilli, I. McHardy, M. G. Mingaliev, S. V. Nazarov, E. Nieppola, K. Nilsson, J. Ohlert, M. Pasanen, D. Porter, T. Pursimo, J. A. Ros, K. Sadakane, A. C. Sadun, S. G. Sergeev, N. Smith, A. Strigachev, N. Sumitomo, L. O. Takalo, K. Tanaka, C. Trigilio, G. Umana, H. Ungerechts, A. Volvach, W. Yuan, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Brightness, Photon, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], quasars: general, 0103 physical sciences, Radiative transfer, quasars: individual: 3C 279, 010303 astronomy & astrophysics, Physics, 010308 nuclear & particles physics, Linear polarization, Astrophysics (astro-ph), Compton scattering, Spectral density, Astronomy and Astrophysics, Light curve, Polarization (waves), Space and Planetary Science
Abstract

We present radio-to-optical data taken by the WEBT, supplemented by VLBA and RXTE observations, of 3C 279. Our goal is to use this extensive database to draw inferences regarding the physics of the relativistic jet. We assemble multifrequency light curves with data from 30 ground-based observatories and the space-based instruments, along with linear polarization vs. time in the optical R band. In addition, we present a sequence of 22 images (with polarization vectors) at 43 GHz at resolution 0.15 milliarcsec, obtained with the VLBA. We analyse the light curves and polarization, as well as the spectral energy distributions at different epochs, corresponding to different brightness states. The IR-optical-UV continuum spectrum of the variable component corresponds to a power law with a constant slope of -1.6, while in the 2.4-10 keV X-ray band it varies in slope from -1.1 to -1.6. The steepest X-ray spectrum occurs at a flux minimum. During a decline in flux from maximum in late 2006, the optical and 43 GHz core polarization vectors rotate by ~300 degrees. The continuum spectrum agrees with steady injection of relativistic electrons with a power-law energy distribution of slope -3.2 that is steepened to -4.2 at high energies by radiative losses. The X-ray emission at flux minimum comes most likely from a new component that starts in an upstream section of the jet where inverse Compton scattering of seed photons from outside the jet is important. The rotation of the polarization vector implies that the jet contains a helical magnetic field that extends ~20 pc past the 43 GHz core., 12 pages, aa.cls style; accepted for publication in A&A

Published
2008

35. The WEBT Campaign on the Blazar 3C279 in 2006

Author

M. Bottcher, S. Basu, M. Joshi, M. Villata, A. Arai, N. Aryan, I. M. Asfandiyarov, U. Bach, R. Bachev, A. Berduygin, M. Blaek, C. Buemi, A. J. Castro‐Tirado, A. De Ugarte Postigo, A. Frasca, L. Fuhrmann, V. A. Hagen‐Thorn, G. Henson, T. Hovatta, R. Hudec, M. Ibrahimov, Y. Ishii, R. Ivanidze, M. Jelinek, M. Kamada, B. Kapanadze, M. Katsuura, D. Kotaka, Y. Y. Kovalev, Yu. A. Kovalev, P. Kubanek, M. Kurosaki, O. Kurtanidze, A. Lahteenmaki, L. Lanteri, V. M. Larionov, L. Larionova, C.‐U. Lee, P. Leto, E. Lindfors, E. Marilli, K. Marshall, H. R. Miller, M. G. Mingaliev, N. Mirabal, S. Mizoguchi, K. Nakamura, E. Nieppola, M. Nikolashvili, K. Nilsson, S. Nishiyama, J. Ohlert, M. A. Osterman, S. Pak, M. Pasanen, C. S. Peters, T. Pursimo, C. M. Raiteri, J. Robertson, T. Robertson, W. T. Ryle, K. Sadakane, A. Sadun, L. Sigua, B.‐W. Sohn, A. Strigachev, N. Sumitomo, L. O. Takalo, Y. Tamesue, K. Tanaka, J. R. Thorstensen, G. Tosti, C. Trigilio, G. Umana, S. Vennes, S. Vitek, A. Volvach, J. Webb, M. Yamanaka, and H.‐S. Yim

Subjects
Physics, Spectral index, Spectral shape analysis, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Magnetic field, Telescope, Space and Planetary Science, law, Low magnetic field, Blazar, Order of magnitude
Abstract

The quasar 3C279 was the target of an extensive multiwavelength monitoring campaign from January through April 2006, including an optical-IR-radio monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we focus on the results of the WEBT campaign. The source exhibited substantial variability of optical flux and spectral shape, with a characteristic time scale of a few days. The variability patterns throughout the optical BVRI bands were very closely correlated with each other. In intriguing contrast to other (in particular, BL Lac type) blazars, we find a lag of shorter- behind longer-wavelength variability throughout the RVB ranges, with a time delay increasing with increasing frequency. Spectral hardening during flares appears delayed with respect to a rising optical flux. This, in combination with the very steep IR-optical continuum spectral index of ~ 1.5 - 2.0, may indicate a highly oblique magnetic field configuration near the base of the jet. An alternative explanation through a slow (time scale of several days) acceleration mechanism would require an unusually low magnetic field of < 0.2 G, about an order of magnitude lower than inferred from previous analyses of simultaneous SEDs of 3C279 and other FSRQs with similar properties., Accepted for publication in ApJ

Published
2007

36. The radio delay of the exceptional 3C 454.3 outburst. Follow-up WEBT observations in 2005-2006

Author

M. Villata, C. M. Raiteri, M. F. Aller, U. Bach, M. A. Ibrahimov, Y. Y. Kovalev, O. M. Kurtanidze, V. M. Larionov, C.-U. Lee, P. Leto, A. Lähteenmäki, K. Nilsson, T. Pursimo, J. A. Ros, N. Sumitomo, A. Volvach, H. D. Aller, A. Arai, C. S. Buemi, J. M. Coloma, V. T. Doroshenko, Yu. S. Efimov, L. Fuhrmann, V. A. Hagen-Thorn, M. Kamada, M. Katsuura, T. Konstantinova, E. Kopatskaya, D. Kotaka, Yu. A. Kovalev, M. Kurosaki, L. Lanteri, L. Larionova, M. G. Mingaliev, S. Mizoguchi, K. Nakamura, M. G. Nikolashvili, S. Nishiyama, K. Sadakane, S. G. Sergeev, L. A. Sigua, A. Sillanpää, R. L. Smart, L. O. Takalo, K. Tanaka, M. Tornikoski, C. Trigilio, and G. Umana

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Phase (waves), Flux, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Light curve, law.invention, Correlation function (statistical mechanics), symbols.namesake, Space and Planetary Science, law, symbols, Radio frequency, Blazar, Doppler effect, Flare
Abstract

In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from the near-IR to the hard X-ray frequencies. A mm outburst peaked in June-July 2005, and it was followed by a flux increase at high radio frequencies. In this paper we report on multifrequency monitoring by the WEBT aimed at following the further evolution of the outburst in detail. In particular, we investigate the expected correlation and time delays between the optical and radio emissions in order to derive information on the variability mechanisms and jet structure. A comparison among the light curves at different frequencies is performed by means of visual inspection and discrete correlation function, and the results are interpreted with a simple model taking into account Doppler factor variations of geometric origin. The high-frequency radio light curves show a huge outburst starting during the dimming phase of the optical one and lasting more than 1 year. The first phase is characterized by a slow flux increase, while in early 2006 a major flare is observed. The lower-frequency radio light curves show a progressively delayed and fainter event, which disappears below 8 GHz. We suggest that the radio major peak is not physically connected with the spring 2005 optical one, but it is actually correlated with a minor optical flare observed in October-November 2005. This interpretation involves both an intrinsic and a geometric mechanism. The former is represented by disturbances travelling down the emitting jet, the latter being due to the curved-jet motion, with the consequent differential changes of viewing angles of the different emitting regions., Comment: 5 pages, 3 figures, to be published in A&A (Letters)

Published
2007
Full Text
View/download PDF

37. WEBT and XMM-Newton observations of 3C 454.3 during the post-outburst phase. Detection of the little and big blue bumps

Author

C. M. Raiteri, M. Villata, V. M. Larionov, T. Pursimo, M. A. Ibrahimov, K. Nilsson, M. F. Aller, O. M. Kurtanidze, L. Foschini, J. Ohlert, I. E. Papadakis, N. Sumitomo, A. Volvach, H. D. Aller, A. A. Arkharov, U. Bach, A. Berdyugin, M. Böttcher, C. S. Buemi, P. Calcidese, P. Charlot, A. J. Delgado Sánchez, A. Di Paola, A. A. Djupvik, M. Dolci, N. V. Efimova, J. H. Fan, E. Forné, C. A. Gomez, A. C. Gupta, V. A. Hagen-Thorn, L. Hooks, T. Hovatta, Y. Ishii, M. Kamada, T. Konstantinova, E. Kopatskaya, Yu. A. Kovalev, Y. Y. Kovalev, A. Lähteenmäki, L. Lanteri, J.-F. Le Campion, C.-U. Lee, P. Leto, H.-C. Lin, E. Lindfors, M. G. Mingaliev, S. Mizoguchi, F. Nicastro, M. G. Nikolashvili, S. Nishiyama, L. Östman, E. Ovcharov, P. Pääkkönen, M. Pasanen, E. Pian, T. Rector, J. A. Ros, K. Sadakane, J. H. Selj, E. Semkov, D. Sharapov, A. Somero, I. Stanev, A. Strigachev, L. Takalo, K. Tanaka, M. Tavani, I. Torniainen, M. Tornikoski, C. Trigilio, G. Umana, S. Vercellone, A. Valcheva, L. Volvach, M. Yamanaka, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Observatoire aquitain des sciences de l'univers (OASU)

Subjects
Brightness, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, galaxies: quasars: individual: 3C 454.3, Astrophysics::Solar and Stellar Astrophysics, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Light curve, Wavelength, Amplitude, galaxies: quasars: general, Space and Planetary Science, Radio frequency
Abstract

The blazar 3C 454.3 underwent an unprecedented optical outburst in spring 2005. This was first followed by a mm and then by a cm radio outburst, which peaked in February 2006. We report on follow-up observations by the WEBT to study the multiwavelength emission in the post-outburst phase. XMM-Newton observations on July and December 2006 added information on the X-ray and UV fluxes. The source was in a faint state. The radio flux at the higher frequencies showed a fast decreasing trend, which represents the tail of the big radio outburst. It was followed by a quiescent state, common at all radio frequencies. In contrast, moderate activity characterized the NIR and optical light curves, with a progressive increase of the variability amplitude with increasing wavelength. We ascribe this redder-when-brighter behaviour to the presence of a "little blue bump" due to line emission from the broad line region, which is clearly visible in the source SED during faint states. Moreover, the data from the XMM-Newton OM reveal a rise of the SED in the UV, suggesting the existence of a "big blue bump" due to thermal emission from the accretion disc. The X-ray spectra are well fitted with a power-law model with photoelectric absorption, possibly larger than the Galactic one. However, the comparison with previous X-ray observations would imply that the amount of absorbing matter is variable. Alternatively, the intrinsic X-ray spectrum presents a curvature, which may depend on the X-ray brightness. In this case, two scenarios are possible., 9 pages, 7 figures, accepted for publication in A&A

Published
2007

38. Multifrequency variability of the blazar AO 0235+164. The WEBT campaign in 2004-2005 and long-term SED analysis

Author

C. M. Raiteri, M. Villata, M. Kadler, M. A. Ibrahimov, O. M. Kurtanidze, V. M. Larionov, M. Tornikoski, P. Boltwood, C.-U. Lee, M. F. Aller, G. E. Romero, H. D. Aller, A. T. Araudo, A. A. Arkharov, U. Bach, D. Barnaby, A. Berdyugin, C. S. Buemi, M. T. Carini, D. Carosati, S. A. Cellone, R. Cool, M. Dolci, N. V. Efimova, L. Fuhrmann, V. A. Hagen-Thorn, M. Holcomb, I. Ilyin, V. Impellizzeri, R. Z. Ivanidze, B. Z. Kapanadze, J. Kerp, T. S. Konstantinova, Y. Y. Kovalev, Yu. A. Kovalev, A. Kraus, T. P. Krichbaum, A. Lähteenmäki, L. Lanteri, P. Leto, E. Lindfors, J. R. Mattox, N. Napoleone, M. G. Nikolashvili, K. Nilsson, J. Ohlert, I. E. Papadakis, M. Pasanen, C. Poteet, T. Pursimo, E. Ros, L. A. Sigua, S. Smith, L. O. Takalo, C. Trigilio, M. Tröller, G. Umana, H. Ungerechts, R. Walters, A. Witzel, and E. Xilouris

Subjects
Ciencias Astronómicas, active [Galaxies], Galaxies: quasars: general, Ciencias Físicas, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, AO 0235+164 (objeto BL Lac), Spectral line, law.invention, Telescope, purl.org/becyt/ford/1 [https], law, Jets, quasars: general [Galaxies], Blazar, Quasars, Ciencias Exactas, Physics, Astrophysics (astro-ph), Spectral density, Astronomy and Astrophysics, Galaxies: active, purl.org/becyt/ford/1.3 [https], Galaxies: BL lacertae objects: individual: AO 0235+164, BL lacertae objects: general [Galaxies], Light curve, Astronomía, BL lacertae objects: individual: AO 0235+164 [Galaxies], Wavelength, Galaxies: jets, Space and Planetary Science, Active galaxies, BL Lacertae objects, jets [Galaxies], Satellite, Radio frequency, Galaxies: BL lacertae objects: general, CIENCIAS NATURALES Y EXACTAS
Abstract

Aims. A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Methods. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. Results. We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. The ∼2600 data points collected allow us to trace the low-energy behaviour of the source in detail, revealing an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to ∼15 GHz, but not at the lower ones. While the X-ray (and optical) light curves obtained during the XMM-Newton pointings reveal no significant short-term variability, the simultaneous intraday radio observations with the 100 m telescope at Effelsberg show flux-density changes at 10.5 GHz, which are more likely due to a combination of intrinsic and extrinsic processes. Conclusions. The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of variability of ∼8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation., La lista completa de autores que integran el documento puede consultarse en el archivo., Facultad de Ciencias Astronómicas y Geofísicas

Published
2006

39. The unprecedented optical outburst of the quasar 3C 454.3. The WEBT campaign of 2004-2005

Author

M. Villata, C. M. Raiteri, T. J. Balonek, M. F. Aller, S. G. Jorstad, O. M. Kurtanidze, F. Nicastro, K. Nilsson, H. D. Aller, A. Arai, A. Arkharov, U. Bach, E. Benítez, A. Berdyugin, C. S. Buemi, M. Böttcher, D. Carosati, R. Casas, A. Caulet, W. P. Chen, P.-S. Chiang, Y. Chou, S. Ciprini, J. M. Coloma, G. Di Rico, C. Díaz, N. V. Efimova, C. Forsyth, A. Frasca, L. Fuhrmann, B. Gadway, S. Gupta, V. A. Hagen-Thorn, J. Harvey, J. Heidt, H. Hernandez-Toledo, F. Hroch, C.-P. Hu, R. Hudec, M. A. Ibrahimov, A. Imada, M. Kamata, T. Kato, M. Katsuura, T. Konstantinova, E. Kopatskaya, D. Kotaka, Y. Y. Kovalev, Yu. A. Kovalev, T. P. Krichbaum, K. Kubota, M. Kurosaki, L. Lanteri, V. M. Larionov, L. Larionova, E. Laurikainen, C.-U. Lee, P. Leto, A. Lähteenmäki, O. López-Cruz, E. Marilli, A. P. Marscher, I. M. McHardy, S. Mondal, B. Mullan, N. Napoleone, M. G. Nikolashvili, J. M. Ohlert, S. Postnikov, T. Pursimo, M. Ragni, J. A. Ros, K. Sadakane, A. C. Sadun, T. Savolainen, E. A. Sergeeva, L. A. Sigua, A. Sillanpää, L. Sixtova, N. Sumitomo, L. O. Takalo, H. Teräsranta, M. Tornikoski, C. Trigilio, G. Umana, A. Volvach, B. Voss, S. Wortel, Aalto-yliopisto, and Aalto University

Subjects
Physics, Brightness, quasars: general [galaxies], Astrophysics::High Energy Astrophysical Phenomena, education, Astrophysics (astro-ph), jets [galaxies], Radio flux, quasars: individual: 3C 454.3 [galaxies], FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Light curve, Viewing angle, law.invention, Telescope, Space and Planetary Science, law, active [galaxies], Radio frequency, Blazar, Astrophysics::Galaxy Astrophysics
Abstract

The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. The maximum brightness detected was R = 12.0, which represents the most luminous quasar state thus far observed (M_B ~ -31.4). In order to follow the emission behaviour of the source in detail, a large multiwavelength campaign was organized by the Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR and radio monitoring was performed in several bands. ToO pointings by the Chandra and INTEGRAL satellites provided additional information at high energies in May 2005. The historical radio and optical light curves show different behaviours. Until about 2001.0 only moderate variability was present in the optical regime, while prominent and long-lasting radio outbursts were visible at the various radio frequencies, with higher-frequency variations preceding the lower-frequency ones. After that date, the optical activity increased and the radio flux is less variable. This suggests that the optical and radio emissions come from two separate and misaligned jet regions, with the inner optical one acquiring a smaller viewing angle during the 2004-2005 outburst. Moreover, the colour-index behaviour (generally redder-when-brighter) during the outburst suggests the presence of a luminous accretion disc. A huge mm outburst followed the optical one, peaking in June-July 2005. The high-frequency (37-43 GHz) radio flux started to increase in early 2005 and reached a maximum at the end of our observing period (end of September 2005). VLBA observations at 43 GHz during the summer confirm the, 7 pages, 4 figures, to be published in A&A

Published
2006

40. The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season : Results from radio-to-optical monitoring and XMM-Newton observations

Author

C. M. Raiteri, M. Villata, M. A. Ibrahimov, V. M. Larionov, M. Kadler, null H .D. Aller, M. F. Aller, Y. Y. Kovalev, L. Lanteri, K. Nilsson, I. E. Papadakis, T. Pursimo, G. E. Romero, H. Teräsranta, M. Tornikoski, A. A. Arkharov, D. Barnaby, A. Berdyugin, M. Böttcher, K. Byckling, M. T. Carini, D. Carosati, S. A. Cellone, S. Ciprini, J. A. Combi, S. Crapanzano, R. Crowe, A. Di Paola, M. Dolci, L. Fuhrmann, M. Gu, V. A. Hagen-Thorn, P. Hakala, V. Impellizzeri, S. Jorstad, J. Kerp, G. N. Kimeridze, Yu. A. Kovalev, A. Kraus, T. P. Krichbaum, O. M. Kurtanidze, A. Lähteenmäki, E. Lindfors, M. G. Mingaliev, R. Nesci, M. G. Nikolashvili, J. Ohlert, M. Orio, L. Ostorero, M. Pasanen, A. Pati, C. Poteet, E. Ros, J. A. Ros, P. Shastri, L. A. Sigua, A. Sillanpää, N. Smith, L. O. Takalo, G. Tosti, A. Vasileva, S. J. Wagner, R. Walters, J. R. Webb, W. Wills, A. Witzel, E. Xilouris, Aalto-yliopisto, and Aalto University

Subjects
Ciencias Astronómicas, individual: AO 0235+16 [BL Lacertae objects], active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), education, galaxies: active, AO+0235%2B16<%2FASTROBJ>%22">BL Lacertae objects: individual: AO 0235+16, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Nordic Optical Telescope, Radio spectrum, law.invention, Radio telescope, Telescope, law, BL Lacertae objects: individual: AO 0235+16, BL Lacertae objects: general, Astrophysics::Galaxy Astrophysics, Physics, general [BL Lacertae objects], Astronomy and Astrophysics, Space and Planetary Science, Brightness temperature, active galaxies, BL Lac objects, jets, Spectral energy distribution, BL Lac object
Abstract

A multiwavelength campaign to observe the BL Lac object AO 0235+16 (z = 0.94) was set up by the Whole Earth Blazar Telescope (WEBT) collaboration during the observing seasons 2003-2004 and 2004-2005, involving radio, near-IR and optical photometric monitoring, VLBA monitoring, optical spectral monitoring, and three pointings by the XMM-Newton satellite. Here we report on the results of the first season, which involved the participation of 24 optical and near-IR telescopes and 4 radio telescopes, as well as the first XMM-Newton pointing, which occurred on January 18-19, 2004. Unpublished data from previous epochs were also collected (from 5 optical-NIR and 3 radio telescopes), in order to fill the gap between the end of the period presented in Raiteri et al. (2001) and the start of the WEBT campaign. The contribution of the southern AGN, 2 arcsec distant from the source, is taken into account. It is found to especially affect the blue part of the optical spectrum when the source is faint. In the optical and near-IR the source has been very active in the last 3 years, although it has been rather faint most of the time, with noticeable variations of more than a magnitude over a few days. In contrast, in the radio bands it appears to have been "quiescent" since early 2000. The major radio (and optical) outburst predicted to peak around February-March 2004 (with a six month uncertainty) has not occurred yet. When comparing our results with the historical light curves, two different behaviours seem to characterize the optical outbursts: only the major events present a radio counterpart. The X-ray spectra obtained by the three EPIC detectors are well fitted by a power law with extra-absorption at z = 0.524; the energy index in the 0.2-10 keV range is well constrained: α = 0.645 ± 0.028 and the 1 keV flux density is 0.311 ± 0.008 μJy. The analysis of the X-ray light curves reveals that no significant variations occurred during the pointing. In contrast, simultaneous dense radio monitoring with the 100 m telescope at Effelsberg shows a ∼2-3% flux decrease in 6-7 h, which, if intrinsic, would imply a brightness temperature well above the Compton limit and hence a lower limit to the Doppler factor δ ≳ 46. We construct the broad-band spectral energy distribution of January 18-19, 2004 with simultaneous radio data from Effelsberg, optical data from the Nordic Optical Telescope (NOT), optical-UV data from the Optical Monitor onboard XMM-Newton, and X-ray data by the EPIC instruments. Particular care is taken to correct data for extinction due to both the Milky Way and the z = 0.524 absorber. The resulting SED suggests the existence of a bump in the UV spectral region., La lista completa de autores que integran el documento puede consultarse en el archivo., Facultad de Ciencias Astronómicas y Geofísicas, Instituto Argentino de Radioastronomía

Published
2005

41. Catching the radio flare in CTA 102

Author

C. M. Fromm, E. Ros, M. Perucho, T. Savolainen, P. Mimica, M. Kadler, A. P. Lobanov, M. L. Lister, Y. Y. Kovalev, and J. A. Zensus

Subjects
Astrofísica, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Kinematics, Astrophysics, 01 natural sciences, law.invention, law, 0103 physical sciences, Very-long-baseline interferometry, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Very Long Baseline Array, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Viewing angle, Light curve, CTA-102, Space and Planetary Science, Astronomia, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Flare
Abstract

We performed multifrequency multiepoch Very Long Baseline Array (VLBA) observations of the blazar CTA 102 during its 2006 radio flare, the strongest ever reported for this source. These observations provide an excellent opportunity to investigate the evolution of the physical properties of blazars, especially during these flaring events. We want to study the kinematic changes in the source during the strong radio outburst in April 2006 and test the assumption of a shock-shock interaction. This assumption is based on the analysis and modeling of the single-dish observations of CTA\,102 (Paper I). In this paper we study the kinematics of CTA 102 at several frequencies using VLBI observations. From the modeled jet features we derived estimates for the evolution of the physical parameters, such as the particle density and the magnetic field. Furthermore, we combined our observations during the 2006 flare with long-term VLBA monitoring of the source at 15 GHz and 43 GHz. We cross-identified seven features throughout our entire multifrequency observations and find evidence of two possible recollimation shocks around 0.1 mas (deprojected 18 pc at a viewing angle of 2.6 degrees) and 6.0 mas (deprojected 1 kpc) from the core. The 43 GHz observations reveal a feature ejected at epoch $t_\mathrm{ej}=2005.9\pm0.2$, which could be connected to the 2006 April radio flare. Furthermore, this feature might be associated with the traveling component involved in the possible shock-shock interaction, which gives rise to the observed double peak structure in the single-dish light curves reported in Paper I., 34 pages, 29 figures, A\& A accepted

Published
2013

44. MOJAVE. XVII. Jet Kinematics and Parent Population Properties of Relativistically Beamed Radio-loud Blazars.

Author

M. L. Lister, D. C. Homan, T. Hovatta, K. I. Kellermann, S. Kiehlmann, Y. Y. Kovalev, W. Max-Moerbeck, A. B. Pushkarev, A. C. S. Readhead, E. Ros, and T. Savolainen

Subjects
RADIO galaxies, LOUDNESS, ACTIVE galactic nuclei, KINEMATICS, MONTE Carlo method, PARAMETERS (Statistics)
Abstract

We present results from a parsec-scale jet kinematics study of 409 bright radio-loud active galactic nuclei (AGNs) based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2016 December 26 as part of the 2 cm VLBA survey and Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) programs. We tracked 1744 individual bright features in 382 jets over at least 5 epochs. A majority (59%) of the best-sampled jet features showed evidence of accelerated motion at the >3σ level. Although most features within a jet typically have speeds within ∼40% of a characteristic median value, we identified 55 features in 42 jets that had unusually slow pattern speeds, nearly all of which lie within 4 pc (100 pc deprojected) of the core feature. Our results, combined with other speeds from the literature, indicate a strong correlation between apparent jet speed and synchrotron peak frequency, with the highest jet speeds being found only in low-peaked AGNs. Using Monte Carlo simulations, we find best-fit parent population parameters for a complete sample of 174 quasars above 1.5 Jy at 15 GHz. Acceptable fits are found with a jet population that has a simple unbeamed power-law luminosity function incorporating pure luminosity evolution and a power-law Lorentz factor distribution ranging from 1.25 to 50 with slope −1.4 ± 0.2. The parent jets of the brightest radio quasars have a space density of 261 ± 19 Gpc−3 and unbeamed 15 GHz luminosities above ∼1024.5 W Hz−1, consistent with FR II class radio galaxies. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

45. Dissecting the AGN Disk–Jet System with Joint VLBI-Gaia Analysis.

Author

A. V. Plavin, Y. Y. Kovalev, and L. Y. Petrov

Subjects
*ACTIVE galactic nuclei, *INTERFEROMETRY, *ACCRETION (Astrophysics), *EMISSIONS (Air pollution), *GALAXIES
Abstract

We analyze differences in positions of active galactic nuclei (AGNs) between Gaia data release 2 and very long baseline interferometry (VLBI) and compare the significant VLBI-to-Gaia offsets in more than 1000 objects with their jet directions. Remarkably at least three-fourths of the significant offsets are confirmed to occur downstream or upstream of the jet representing a genuine astrophysical effect. Introducing redshift and Gaia color into analysis can help distinguish between the contribution of the host galaxy, jet, and accretion disk emission. We find that strong optical jet emission at least 20–50 pc long is required to explain the Gaia positions located downstream from VLBI ones. Offsets in the upstream direction of up to 2 mas are at least partly due to the dominant impact of the accretion disk on the Gaia coordinates and by the effects of the parsec-scale radio jet. The host galaxy was found not to play an important role in the detected offsets. BL Lacertae object and Seyfert 2 galaxies are observationally confirmed to have a relatively weak disk and consequently downstream offsets. The disk emission drives upstream offsets in a significant fraction of quasars and Seyfert 1 galaxies when it dominates over the jet in the optical band. The observed behavior of the different AGN classes is consistent with the unified scheme assuming varying contribution of the obscuring dusty torus and jet beaming. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

46. MOJAVE XVI: Multiepoch Linear Polarization Properties of Parsec-scale AGN Jet Cores.

Author

M. A. Hodge, M. L. Lister, M. F. Aller, H. D. Aller, Y. Y. Kovalev, A. B. Pushkarev, and T. Savolainen

Subjects
LINEAR polarization, OPTICAL polarization, LINEAR polarizers, ACTIVE galactic nuclei, ACTIVE galaxies, GALACTIC nuclei, SYNCHROTRONS
Abstract

We present an analysis of the core linear polarization properties of 387 parsec-scale active galactic nuclei (AGNs) jets. Using 15 GHz VLBA data, we revisit the conclusions of the first paper in this series with multiepoch measurements and more detailed analysis of a larger AGN sample that spans a broader range of synchrotron peak frequencies. Each AGN has been observed for at least five epochs between 1996 and 2017. We find that BL Lac objects have core electric vector position angles (EVPAs) that tend toward alignment with the local jet direction; compared to flat spectrum radio quasars, their EVPAs are also less variable over time. The AGN cores that are most fractionally polarized and least variable in polarization have EVPAs that are closely aligned with the local jet direction; they also have low variability in EVPA. These results support the popular model of a standing transverse shock at the base of the jet that collimates the jet magnetic field perpendicular to the jet direction, increasing the fractional polarization and leading to greater polarization stability over time. High-synchrotron-peaked BL Lac objects form a low luminosity, low fractional polarization population. The five narrow line Seyfert 1 galaxies in our sample have low fractional polarization and large EVPA-jet misalignments. Although AGNs detected at γ-rays are thought to be more Doppler boosted than nondetected AGNs, we find no significant differences in fractional polarization based on detection by Fermi-LAT; the γ-loud AGNs are, however, more variable in core EVPAs. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

47. Reversals in the Direction of Polarization Rotation in OJ 287.

Author

M. H. Cohen, H. D. Aller, M. F. Aller, T. Hovatta, P. Kharb, Y. Y. Kovalev, M. L. Lister, D. L. Meier, A. B. Pushkarev, and T. Savolainen

Subjects
POLARIZATION (Nuclear physics), ACTINIC flux, BL Lacertae objects, STELLAR rotation, WAVELENGTHS
Abstract

We have obtained a smooth time series for the electric vector position angle (EVPA) of the blazar OJ 287 at centimeter wavelengths, by making ±nπ adjustments to archival values from 1974 to 2016. The data display rotation reversals in which the EVPA rotates counterclockwise for ∼180° and then rotates clockwise by a similar amount. The timescale of the rotations is a few weeks to a year, and the scale for a double rotation, including the reversal, is 1–3 yr. We have seen four of these events in 40 yr. A model consisting of two successive outbursts in polarized flux density, with EVPAs counterrotating, superposed on a steady polarized jet, can explain many of the details of the observations. Polarization images support this interpretation. The model can also help to explain similar events seen at optical wavelengths. The outbursts needed for the model can be generated by the supermagnetosonic jet model of Nakamura et al. and Nakamura & Meier, which requires a strong helical magnetic field. This model produces forward and reverse pairs of fast and slow MHD waves, and the plasma inside the two fast/slow pairs rotates around the jet axis, but in opposite directions. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

49. A NEARLY NAKED SUPERMASSIVE BLACK HOLE.

Author

J. J. Condon, Jeremy Darling, Y. Y. Kovalev, and L. Petrov

Subjects
BLACK holes, GALAXY clusters, GALACTIC nuclei, RADIAL velocity of galaxies, RADIO galaxies
Abstract

During a systematic search for supermassive black holes (SMBHs) not in galactic nuclei, we identified the compact, symmetric radio source B3 1715+425 with an emission-line galaxy offset from the nucleus of the brightest cluster galaxy (BCG) in the redshift z = 0.1754 cluster ZwCl 8193. B3 1715+425 is too bright (brightness temperature at observing frequency ) and too luminous (1.4 GHz luminosity ) to be powered by anything but an SMBH, but its host galaxy is much smaller ( full width between half-maximum points) and optically fainter (R-band absolute magnitude ) than any other radio galaxy. Its high radial velocity relative to the BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding debris indicate that the radio galaxy was tidally shredded passing through the BCG core, leaving a nearly naked SMBH fleeing from the BCG with space velocity . The radio galaxy has mass and infrared luminosity close to its dust Eddington limit, so it is vulnerable to further mass loss from radiative feedback. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results