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4 results on '"G. Apolonio"'

1. Multimessenger Characterization of Markarian 501 during Historically Low X-Ray and γ-Ray Activity

Author

H. Abe, S. Abe, V. A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, I. Burelli, G. Busetto, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, G. Ceribella, Y. Chai, A. Chilingarian, S. Cikota, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, V. Fallah Ramazani, L. Fariña, A. Fattorini, L. Foffano, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau, D. Green, J. G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, E. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, H. A. Mondal, A. Moralejo, D. Morcuende, V. Moreno, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, T. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P. G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J. L. Schubert, T. Schweizer, J. Sitarek, V. Sliusar, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C. F. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, The MAGIC Collaboration, M. Cerruti, J. A. Acosta-Pulido, G. Apolonio, R. Bachev, M. Baloković, E. Benítez, I. Björklund, V. Bozhilov, L. F. Brown, A. Bugg, W. Carbonell, M. I. Carnerero, D. Carosati, C. Casadio, W. Chamani, W. P. Chen, R. A. Chigladze, G. Damljanovic, K. Epps, A. Erkenov, M. Feige, J. Finke, A. Fuentes, K. Gazeas, M. Giroletti, T. S. Grishina, A. C. Gupta, M. A. Gurwell,, E. Heidemann, D. Hiriart, W. J. Hou, T. Hovatta, S. Ibryamov, M. D. Joner, S. G. Jorstad, J. Kania, S. Kiehlmann, G. N. Kimeridze, E. N. Kopatskaya, M. Kopp, M. Korte, B. Kotas, S. Koyama, J. A. Kramer, L. Kunkel, S. O. Kurtanidze, O. M. Kurtanidze, A. Lähteenmäki, J. M. López, V. M. Larionov, E. G. Larionova, L. V. Larionova, C. Leto, C. Lorey, R. Mújica, G. M. Madejski, N. Marchili, A. P. Marscher, M. Minev, A. Modaressi, D. A. Morozova, T. Mufakharov, I. Myserlis, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, M. Perri, C. M. Raiteri, A. C. S. Readhead, A. Reimer, D. Reinhart, S. Righini, K. Rosenlehner, A. C. Sadun, S. S. Savchenko, A. Scherbantin, L. Schneider, K. Schoch, D. Seifert, E. Semkov, L. A. Sigua, C. Singh, P. Sola, Y. Sotnikova, M. Spencer, R. Steineke, M. Stojanovic, A. Strigachev, M. Tornikoski, E. Traianou, A. Tramacere, Yu. V. Troitskaya, I. S. Troitskiy, J. B. Trump, A. Tsai, A. Valcheva, A. A. Vasilyev, F. Verrecchia, M. Villata, O. Vince, K. Vrontaki, Z. R. Weaver, E. Zaharieva, and N. Zottmann

Subjects
Active galaxies, BL Lacertae objects, Markarian galaxies, Active galactic nuclei, Blazars, Astrophysics, QB460-466
Abstract

We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) γ -rays. A significant correlation (>3 σ ) between X-rays and VHE γ -rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ -rays and radio, with the radio lagging by more than 100 days, placing the γ -ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE γ -rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.

Published
2023
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2. Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae

Author

S. G. Jorstad, A. P. Marscher, C. M. Raiteri, M. Villata, Z. R. Weaver, H. Zhang, L. Dong, J. L. Gómez, M. V. Perel, S. S. Savchenko, V. M. Larionov, D. Carosati, W. P. Chen, O. M. Kurtanidze, A. Marchini, K. Matsumoto, F. Mortari, P. Aceti, J. A. Acosta-Pulido, T. Andreeva, G. Apolonio, C. Arena, A. Arkharov, R. Bachev, M. Banfi, G. Bonnoli, G. A. Borman, V. Bozhilov, M. I. Carnerero, G. Damljanovic, S. A. Ehgamberdiev, D. Elsässer, A. Frasca, D. Gabellini, T. S. Grishina, A. C. Gupta, V. A. Hagen-Thorn, M. K. Hallum, M. Hart, K. Hasuda, F. Hemrich, H. Y. Hsiao, S. Ibryamov, T. R. Irsmambetova, D. V. Ivanov, M. D. Joner, G. N. Kimeridze, S. A. Klimanov, J. Knött, E. N. Kopatskaya, S. O. Kurtanidze, A. Kurtenkov, T. Kuutma, E. G. Larionova, S. Leonini, H. C. Lin, C. Lorey, K. Mannheim, G. Marino, M. Minev, D. O. Mirzaqulov, D. A. Morozova, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, R. Papini, T. Pursimo, I. Rahimov, D. Reinhart, T. Sakamoto, F. Salvaggio, E. Semkov, D. N. Shakhovskoy, L. A. Sigua, R. Steineke, M. Stojanovic, A. Strigachev, Y. V. Troitskaya, I. S. Troitskiy, A. Tsai, A. Valcheva, A. A. Vasilyev, O. Vince, L. Waller, E. Zaharieva, R. Chatterjee, Ministerio de Ciencia e Innovación (España), and European Commission

Subjects
High-energy astrophysics, Multidisciplinary, Astrophysical magnetic fields, High-energy astrophysics, Time-domain astronomy, Time-domain astronomy, Astrophysical magnetic fields
Abstract

Full list of authors: Jorstad, S. G.; Marscher, A. P.; Raiteri, C. M.; Villata, M.; Weaver, Z. R.; Zhang, H.; Dong, L.; Gomez, J. L.; Perel, M., V; Savchenko, S. S.; Larionov, V. M.; Carosati, D.; Chen, W. P.; Kurtanidze, O. M.; Marchini, A.; Matsumoto, K.; Mortari, F.; Aceti, P.; Acosta-Pulido, J. A.; Andreeva, T.; Apolonio, G.; Arena, C.; Arkharov, A.; Bachev, R.; Bonnoli, G.; Borman, G. A.; Bozhilov, V; Carnerero, M., I; Damljanovic, G.; Ehgamberdiev, S. A.; Elsasser, D.; Frasca, A.; Gabellini, D.; Grishina, T. S.; Gupta, A. C.; Hagen-Thorn, V. A.; Hallum, M. K.; Hart, M.; Hasuda, K.; Hemrich, F.; Hsiao, H. Y.; Ibryamov, S.; Irsmambetova, T. R.; Ivanov, D., V; Joner, M. D.; Kimeridze, G. N.; Klimanov, S. A.; Knoett, J.; Kopatskaya, E. N.; Kurtanidze, S. O.; Kurtenkov, A.; Kuutma, T.; Larionova, E. G.; Leonini, S.; Lin, H. C.; Lorey, C.; Mannheim, K.; Marino, G.; Minev, M.; Mirzaqulov, D. O.; Morozova, D. A.; Nikiforova, A. A.; Nikolashvili, M. G.; Ovcharov, E.; Papini, R.; Pursimo, T.; Rahimov, I; Reinhart, D.; Sakamoto, T.; Salvaggio, F.; Semkov, E.; Shakhovskoy, D. N.; Sigua, L. A.; Steineke, R.; Stojanovic, M.; Strigachev, A.; Troitskaya, Y., V; Troitskiy, I. S.; Tsai, A.; Valcheva, A.; Vasilyev, A. A.; Vince, O.; Waller, L.; Zaharieva, E.; Chatterjee, R., Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales1,2,3. This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare4 in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet5, plasma instabilities6,7 or orbital motion in an accretion disc7,8. Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref. 9). BL Lac, the prototype of a subclass of blazars10, is powered by a 1.7 × 108 MSun (ref. 11) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref. 12)). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities6 near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image. © 2022 Springer Nature Limited., The research reported here is based on work supported in part by US National Science Foundation grants AST-2108622 and AST-2107806, and NASA Fermi GI grants 80NSSC20K1567, 80NSSC21K1917 and 80NSSC21K1951; by Shota Rustaveli National Science Foundation of Georgia under contract FR-19-6174; by the Bulgarian National Science Fund of the Ministry of Education and Science under grants DN 18-10/2017, DN 18-13/2017, KP-06-H28/3 (2018), KP-06-H38/4 (2019) and KP-06-KITAJ/2 (2020), and by National RI Roadmap Project D01-383/18.12.2020 of the Ministry of Education and Science of the Republic of Bulgaria; by JSPS KAKENHI grant #19K03930 of Japan; by the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract 451-03-9/2021-14/200002) and observing grant support from the Institute of Astronomy and Rozhen NAO BAS through the bilateral joint research project ‘Gaia Celestial Reference Frame (CRF) and fast variable astronomical objects’; by the Agenzia Spaziale Italiana (ASI) through contracts I/037/08/0, I/058/10/0, 2014-025-R.0, 2014-025-R.1.2015 and 2018-24-HH.0 to the Italian Istituto Nazionale di Astrofisica (INAF). H.Z. is supported by the NASA Postdoctoral Program at Goddard Space Flight Center, administered by ORAU. M.V.P. is partially supported by the Russian Foundation for Basic Research grant 20-02-00490. G.B. acknowledges support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and from the Spanish ‘Ministerio de Ciencia e Innovacíon’ (MICINN) through grant PID2019-107847RB-C44. M.D.J. thanks the Brigham Young University Department of Physics and Astronomy for continued support of the extragalactic monitoring programme under way at the West Mountain Observatory. R.C. thanks ISRO for support under the AstroSat archival data utilization programme and BRNS for support through a project grant (sanction no. 57/14/10/2019-BRNS). The measurements at the Hans Haffner Observatory, Hettstadt, Germany, were supported by Baader Planetarium, Mammendorf, Germany. This study was based (in part) on observations conducted using the 1.8-m Perkins Telescope Observatory (PTO) in Arizona, USA, which is owned and operated by Boston University. These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell Observatory is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy, and operates the LDT in partnership with Boston University, the University of Maryland and the University of Toledo. This paper is partly based on observations made with the IAC-80 operated on the island of Tenerife by the Instituto de Astrofisica de Canarias in the Spanish Observatorio del Teide and on observations made with the LCOGT telescopes, one of whose nodes is located at the Observatorios de Canarias del IAC on the island of Tenerife in the Observatorio del Teide. This paper is partly based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The VLBA is an instrument of the NRAO, USA. The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Published
2022

3. The optical behaviour of BL Lacertae at its maximum brightness levels: a blend of geometry and energetics

Author

C M Raiteri, M Villata, S G Jorstad, A P Marscher, J A Acosta Pulido, D Carosati, W P Chen, M D Joner, S O Kurtanidze, C Lorey, A Marchini, K Matsumoto, D O Mirzaqulov, S S Savchenko, A Strigachev, O Vince, P Aceti, G Apolonio, C Arena, A Arkharov, R Bachev, N Bader, M Banfi, G Bonnoli, G A Borman, V Bozhilov, L F Brown, W Carbonell, M I Carnerero, G Damljanovic, V Dhiman, S A Ehgamberdiev, D Elsaesser, M Feige, D Gabellini, D Galán, G Galli, H Gaur, K Gazeas, T S Grishina, A C Gupta, V A Hagen-Thorn, M K Hallum, M Hart, K Hasuda, K Heidemann, B Horst, W-J Hou, S Ibryamov, R Z Ivanidze, M D Jovanovic, G N Kimeridze, S Kishore, S Klimanov, E N Kopatskaya, O M Kurtanidze, P Kushwaha, D J Lane, E G Larionova, S Leonini, H C Lin, K Mannheim, G Marino, M Minev, A Modaressi, D A Morozova, F Mortari, S V Nazarov, M G Nikolashvili, J Otero Santos, E Ovcharov, R Papini, V Pinter, C A Privitera, T Pursimo, D Reinhart, J Roberts, F D Romanov, K Rosenlehner, T Sakamoto, F Salvaggio, K Schoch, E Semkov, J Seufert, D Shakhovskoy, L A Sigua, C Singh, R Steineke, M Stojanovic, T Tripathi, Y V Troitskaya, I S Troitskiy, A Tsai, A Valcheva, A A Vasilyev, K Vrontaki, Z R Weaver, J H F Wooley, E Zaharieva, and A V Zhovtan

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

In 2021 BL Lacertae underwent an extraordinary activity phase, which was intensively followed by the Whole Earth Blazar Telescope (WEBT) Collaboration. We present the WEBT optical data in the BVRI bands acquired at 36 observatories around the world. In mid 2021 the source showed its historical maximum, with R = 11.14. The light curves display many episodes of intraday variability, whose amplitude increases with source brightness, in agreement with a geometrical interpretation of the long-term flux behaviour. This is also supported by the long-term spectral variability, with an almost achromatic trend with brightness. In contrast, short-term variations are found to be strongly chromatic and are ascribed to energetic processes in the jet. We also analyse the optical polarimetric behaviour, finding evidence of a strong correlation between the intrinsic fast variations in flux density and those in polarisation degree, with a time delay of about 13 h. This suggests a common physical origin. The overall behaviour of the source can be interpreted as the result of two mechanisms: variability on time scales greater than several days is likely produced by orientation effects, while either shock waves propagating in the jet, or magnetic reconnection, possibly induced by kink instabilities in the jet, can explain variability on shorter time scales. The latter scenario could also account for the appearance of quasi-periodic oscillations, with periods from a few days to a few hours, during outbursts, when the jet is more closely aligned with our line of sight and the time scales are shortened by relativistic effects., Comment: 15 pages, 16 figures, submitted to MNRAS

Published
2023
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4. Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae.

Author

Jorstad SG, Marscher AP, Raiteri CM, Villata M, Weaver ZR, Zhang H, Dong L, Gómez JL, Perel MV, Savchenko SS, Larionov VM, Carosati D, Chen WP, Kurtanidze OM, Marchini A, Matsumoto K, Mortari F, Aceti P, Acosta-Pulido JA, Andreeva T, Apolonio G, Arena C, Arkharov A, Bachev R, Banfi M, Bonnoli G, Borman GA, Bozhilov V, Carnerero MI, Damljanovic G, Ehgamberdiev SA, Elsässer D, Frasca A, Gabellini D, Grishina TS, Gupta AC, Hagen-Thorn VA, Hallum MK, Hart M, Hasuda K, Hemrich F, Hsiao HY, Ibryamov S, Irsmambetova TR, Ivanov DV, Joner MD, Kimeridze GN, Klimanov SA, Knött J, Kopatskaya EN, Kurtanidze SO, Kurtenkov A, Kuutma T, Larionova EG, Leonini S, Lin HC, Lorey C, Mannheim K, Marino G, Minev M, Mirzaqulov DO, Morozova DA, Nikiforova AA, Nikolashvili MG, Ovcharov E, Papini R, Pursimo T, Rahimov I, Reinhart D, Sakamoto T, Salvaggio F, Semkov E, Shakhovskoy DN, Sigua LA, Steineke R, Stojanovic M, Strigachev A, Troitskaya YV, Troitskiy IS, Tsai A, Valcheva A, Vasilyev AA, Vince O, Waller L, Zaharieva E, and Chatterjee R

Abstract

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales 1-3 . This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare 4 in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet 5 , plasma instabilities 6,7 or orbital motion in an accretion disc 7,8 . Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref.  9 ). BL Lac, the prototype of a subclass of blazars 10 , is powered by a 1.7 × 10 8  M Sun (ref.  11 ) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref.  12 )). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities 6 near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2022
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