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1. Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and γ-ray brightness levels

Author

C M Raiteri, M Villata, M I Carnerero, S S Savchenko, S O Kurtanidze, V V Vlasyuk, A Marchini, K Matsumoto, C Lorey, M D Joner, K Gazeas, D Carosati, D O Mirzaqulov, J A Acosta Pulido, I Agudo, R Bachev, E Benítez, G A Borman, P Calcidese, W P Chen, G Damljanovic, S A Ehgamberdiev, D Elsässer, M Feige, A Frasca, H Gaur, T S Grishina, A C Gupta, D Hiriart, M Holland, B Horst, S Ibryamov, R Z Ivanidze, J Jensen, V Jithesh, M D Jovanovic, S Kiehlmann, G N Kimeridze, S Kishore, E N Kopatskaya, O M Kurtanidze, E G Larionova, H C Lin, K Mannheim, C Marinelli, J Moreira Reyes, D A Morozova, M G Nikolashvili, D Reinhart, F D Romanov, E Semkov, J Seufert, E V Shishkina, L A Sigua, R Skalidis, O I Spiridonova, M Stojanovic, A Strigachev, Y V Troitskaya, I S Troitskiy, A Tsai, A A Vasilyev, O Vince, K Vrontaki, K Wani, D Watts, and A V Zhovtan

Published
2023
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2. Multiband Optical Variability of the Blazar 3C 454.3 on Diverse Timescales

Author

Karan Dogra, Alok C. Gupta, C. M. Raiteri, M. Villata, Paul J. Wiita, S. O. Kurtanidze, S. G. Jorstad, R. Bachev, G. Damljanovic, C. Lorey, S. S. Savchenko, O. Vince, M. Abdelkareem, F. J. Aceituno, J. A. Acosta-Pulido, I. Agudo, G. Andreuzzi, S. A. Ata, G. V. Baida, L. Barbieri, D. A. Blinov, G. Bonnoli, G. A. Borman, M. I. Carnerero, D. Carosati, V. Casanova, W. P. Chen, Lang Cui, E. G. Elhosseiny, D. Elsaesser, J. Escudero, M. Feige, K. Gazeas, L. E. Gennadievna, T. S. Grishina, Minfeng Gu, V. A. Hagen-Thorn, F. Hemrich, H. Y. Hsiao, M. Ismail, R. Z. Ivanidze, M. D. Jovanovic, T. M. Kamel, G. N. Kimeridze, E. N. Kopatskaya, D. Kuberek, O. M. Kurtanidze, A. Kurtenkov, V. M. Larionov, L. V. Larionova, M. Liao, H. C. Lin, K. Mannheim, A. Marchini, C. Marinelli, A. P. Marscher, D. Morcuende, D. A. Morozova, S. V. Nazarov, M. G. Nikolashvili, D. Reinhart, J. O. Santos, A. Scherbantin, E. Semkov, E. V. Shishkina, L. A. Sigua, A. K. Singh, A. Sota, R. Steineke, M. Stojanovic, A. Strigachev, A. Takey, Amira A. Tawfeek, I. S. Troitskiy, Y. V. Troitskaya, An-Li Tsai, A. A. Vasilyev, K. Vrontaki, Zhongli Zhang, A. V. Zhovtan, N. Zottmann, and Wenwen Zuo

Subjects
Active galactic nuclei, Blazars, Flat-spectrum radio quasars, Markov chain Monte Carlo, Relativistic jets, Supermassive black holes, Astrophysics, QB460-466
Abstract

Due to its peculiar and highly variable nature, the blazar 3C 454.3 has been extensively monitored by the WEBT team. Here, we present for the first time these long-term optical flux and color variability results using data acquired in B , V , R , and I bands over a time span of about two decades. We include data from WEBT collaborators and public archives such as SMARTS, Steward Observatory, and Zwicky Transient Facility. The data are binned and segmented to study the source over this long term when more regular sampling was available. During our study, the long-term spectral variability reveals a redder-when-brighter trend, which, however, stabilizes at a particular brightness cutoff of ∼14.5 mag in the I band, after which it saturates and evolves into a complex state. This trend indicates increasing dominance of jet emission over accretion disk (AD) emission until jet emission completely dominates. Plots of the variation in spectral index (following F _ν ∝ ν ^− ^α ) reveal a bimodal distribution using a one-day binning. These correlate with two extreme phases of 3C 454.3, an outburst or high-flux state and a quiescent or low-flux state, which are respectively jet- and AD-dominated. We have also conducted intraday variability studies of nine light curves and found that six of them are variable. Discrete correlation function analysis between different pairs of optical wave bands peaks at zero lags, indicating cospatial emission in different optical bands.

Published
2024
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3. 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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4. The dual nature of blazar fast variability: Space and ground observations of S5 0716+714

Author

C M Raiteri, M Villata, D Carosati, E Benítez, S O Kurtanidze, A C Gupta, D O Mirzaqulov, F D’Ammando, V M Larionov, T Pursimo, J A Acosta-Pulido, G V Baida, B Balmaverde, G Bonnoli, G A Borman, M I Carnerero, W-P Chen, V Dhiman, A Di Maggio, S A Ehgamberdiev, D Hiriart, G N Kimeridze, O M Kurtanidze, C S Lin, J M Lopez, A Marchini, K Matsumoto, R Mujica, M Nakamura, A A Nikiforova, M G Nikolashvili, D N Okhmat, J Otero-Santos, N Rizzi, T Sakamoto, E Semkov, L A Sigua, L Stiaccini, I S Troitsky, A L Tsai, A A Vasilyev, and A V Zhovtan

Published
2020
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5. 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
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6. Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013–2017

Author

F D’Ammando, C M Raiteri, M Villata, J A Acosta-Pulido, I Agudo, A A Arkharov, R Bachev, G V Baida, E Benítez, G A Borman, W Boschin, V Bozhilov, M S Butuzova, P Calcidese, M I Carnerero, D Carosati, C Casadio, N Castro-Segura, W-P Chen, G Damljanovic, A Di Paola, J Echevarría, N V Efimova, Sh A Ehgamberdiev, C Espinosa, A Fuentes, A Giunta, J L Gómez, T S Grishina, M A Gurwell, D Hiriart, H Jermak, B Jordan, S G Jorstad, M Joshi, G N Kimeridze, E N Kopatskaya, K Kuratov, O M Kurtanidze, S O Kurtanidze, A Lähteenmäki, V M Larionov, E G Larionova, L V Larionova, C Lázaro, C S Lin, M P Malmrose, A P Marscher, K Matsumoto, B McBreen, R Michel, B Mihov, M Minev, D O Mirzaqulov, S N Molina, J W Moody, D A Morozova, S V Nazarov, A A Nikiforova, M G Nikolashvili, J M Ohlert, N Okhmat, E Ovcharov, F Pinna, T A Polakis, C Protasio, T Pursimo, F J Redondo-Lorenzo, N Rizzi, G Rodriguez-Coira, K Sadakane, A C Sadun, M R Samal, S S Savchenko, E Semkov, L Sigua, B A Skiff, L Slavcheva-Mihova, P S Smith, I A Steele, A Strigachev, J Tammi, C Thum, M Tornikoski, Yu V Troitskaya, I S Troitsky, A A Vasilyev, O Vince, T Hovatta, S Kiehlmann, W Max-Moerbeck, A C S Readhead, R Reeves, T J Pearson, T Mufakharov, Yu V Sotnikova, and M G Mingaliev

Published
2019
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7. The beamed jet and quasar core of the distant blazar 4C 71.07

Author

C M Raiteri, M Villata, M I Carnerero, J A Acosta-Pulido, D O Mirzaqulov, V M Larionov, P Romano, S Vercellone, I Agudo, A A Arkharov, U Bach, R Bachev, S Baitieri, G A Borman, W Boschin, V Bozhilov, M S Butuzova, P Calcidese, D Carosati, C Casadio, W-P Chen, G Damljanovic, A Di Paola, V T Doroshenko, N V Efimova, Sh A Ehgamberdiev, M Giroletti, J L Gómez, T S Grishina, S Ibryamov, H Jermak, S G Jorstad, G N Kimeridze, S A Klimanov, E N Kopatskaya, O M Kurtanidze, S O Kurtanidze, A Lähteenmäki, E G Larionova, A P Marscher, B Mihov, M Minev, S N Molina, J W Moody, D A Morozova, S V Nazarov, A A Nikiforova, M G Nikolashvili, E Ovcharov, S Peneva, S Righini, N Rizzi, A C Sadun, M R Samal, S S Savchenko, E Semkov, L A Sigua, L Slavcheva-Mihova, I A Steele, A Strigachev, M Tornikoski, Yu V Troitskaya, I S Troitsky, and O Vince

Published
2019
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8. 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
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9. Uncovering the host galaxy of the γ-ray-emitting narrow-line Seyfert 1 galaxy FBQS J1644+2619

Author

Ranieri D. Baldi, Alessandro Capetti, Filippo D'Ammando, C. Ramos Almeida, M. Orienti, C. M. Raiteri, J. A. Acosta-Pulido, ITA, and ESP

Subjects
Luminous infrared galaxy, Physics, Active galactic nucleus, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Type-cD galaxy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Space and Planetary Science, Bulge, 0103 physical sciences, Elliptical galaxy, Astrophysics::Earth and Planetary Astrophysics, Surface brightness, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract

The discovery of $\gamma$-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies has questioned the need for large black hole masses (> 10$^8$ M$_{\odot}$) to launch relativistic jets. We present near-infrared data of the $\gamma$-ray-emitting NLSy1 FBQS J1644+2619 that were collected using the camera CIRCE (Canarias InfraRed Camera Experiment) at the 10.4-m Gran Telescopio Canarias to investigate the structural properties of its host galaxy and to infer the black hole mass. The 2D surface brightness profile is modelled by the combination of a nuclear and a bulge component with a S\'ersic profile with index $n$ = 3.7, indicative of an elliptical galaxy. The structural parameters of the host are consistent with the correlations of effective radius and surface brightness against absolute magnitude measured for elliptical galaxies. From the bulge luminosity, we estimated a black hole mass of (2.1$\pm$0.2) $\times$10$^8$ M$_{\odot}$, consistent with the values characterizing radio-loud active galactic nuclei., Comment: 5 pages, 3 figures, 1 table. Monthly Notices of the Royal Astronomical Society Letter, Vol. 469, L11-L15

Published
2017
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10. Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

Author

P. A. González-Morales, Valeri M. Larionov, Filippo D'Ammando, C. Lázaro, Sergey S. Savchenko, Ivan Agudo, V. Bozhilov, A. B. Grinon-Marin, Michael D. Joner, F. J. Redondo-Lorenzo, Sol N. Molina, Svetlana Boeva, A. Pastor Yabar, C. Pace, C. Protasio, M. G. Nikolashvili, M. J. Arévalo, E. Eswaraiah, D. A. Morozova, E. N. Kopatskaya, Sofia O. Kurtanidze, O. Vince, Carolina Casadio, Evgeni Ovcharov, Yu. V. Troitskaya, Joseph Moody, G. Gantchev, Svetlana G. Jorstad, Ekaterina Koptelova, L. Slavcheva-Mihova, A. A. Vasilyev, B. Jordan, Marcus Holden, Sunay Ibryamov, Ivan S. Troitsky, R. Ligustri, Kari Nilsson, Rumen Bachev, Wen Ping Chen, Elena G. Larionova, Alan P. Marscher, N. Rizzi, J. Barnes, F. Pinna, B. McBreen, G. Rodriguez-Coira, J. A. Acosta-Pulido, D. Carosati, Georgi Latev, A. C. Sadun, T. S. Grishina, J. A. Ros, Goran Damljanović, Evgeni Semkov, Neelam Panwar, Manasvita Joshi, H. C. Lin, Boyko Mihov, E. Forné, José L. Gómez, C. Martínez-Lombilla, M. I. Carnerero, A. Strigachev, Nathan Smith, O. M. Kurtanidze, Paul S. Smith, M. Villata, L. V. Larionova, C. M. Raiteri, R. Pearson, Ministerio de Economía y Competitividad (España), Russian Science Foundation, Junta de Andalucía, Bulgarian Academy of Sciences, Ministry of Education, Science and Technological Development (Serbia), and National Aeronautics and Space Administration (US)

Subjects
Galaxies: active, Galaxies: jets, Astrophysics::High Energy Astrophysical Phenomena, jets [galaxies], Library science, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, Observatory, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), individual: Mrk 421 [BL Lacertae objects], ta115, 010308 nuclear & particles physics, general [BL Lacertae objects], Astronomy and Astrophysics, BL Lacertae objects: general, Joint research, 13. Climate action, Space and Planetary Science, active [galaxies], BL Lacertae objects: individual: Mrk 421, Christian ministry, Astrophysics - High Energy Astrophysical Phenomena, active, Galaxies: jets [Galaxies]
Abstract

We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by several extreme flares. The ratio between the optical, X-ray and γ-ray fluxes is very variable. The γ-ray flux variations show a fair correlation with the optical ones starting from 2012. We analyse spectropolarimetric data and find wavelength-dependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA. We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of ~50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society., The Abastumani team acknowledges financial support by Shota Rustaveli NSF under contract FR/577/6-320/13. The research at BU was supported in part by US National Science Foundation grant AST-1615796 and NASA Fermi Guest Investigator grant NNX14AQ58G. This study makes use of 43 GHz VLBA data from the VLBA-BU Blazar Monitoring Program (VLBA-BUBLAZAR; http://www.bu.edu/blazars/VLBAproject.html), funded by NASA through the Fermi Guest Investigator Program. The PRISM camera at the Lowell Observatory was developed by K. Janes et al. at the BU and Lowell Observatory, with funding from the NSF, BU and Lowell Observatory. This research has made use of data from the MOJAVE data base, which is maintained by the MOJAVE team (Lister et al. 2009). The St. Petersburg University team acknowledges support from Russian RFBR grant 15-02-00949 and St. Petersburg University research grant 6.38.335.2015. This paper is partly based on observations carried out at the German Spanish Calar Alto Observatory, which is jointly operated by the MPIA and the IAA-CSIC. IA research is supported by a Ramon y Cajal grant of the Spanish Ministerio de Economia y Competitividad (MINECO). Acquisition of the MAPCAT data was supported in part by MINECO through grants AYA2010-14844, AYA2013-40825-P and AYA2016-80889-P, and by the Regional Government of Andalucia through grant P09-FQM-4784. This research was partially supported by the Scientific Research Fund of the Bulgarian Ministry of Education and Sciences under grants DO 02-137 (BIn-13/09) and DN 08/1. The Skinakas Observatory is a collaborative project of the University of Crete, the Foundation for Research and Technology - Hellas and the Max-Planck-Institut fur Extrater-restrische Physik. GD and OV gratefully acknowledge the observing grant support from the Institute of Astronomy and Rozhen National Astronomical Observatory, Bulgaria Academy of Sciences, via the bilateral joint research project 'Observations of ICRF radio-sources visible in optical domain' (the head is Dr G. Damljanovic). This work is a part of the Projects No 176011 ('Dynamics and kinematics of celestial bodies and systems'), No 176004 ('Stellar physics') and No 176021 ('Visible and invisible matter in nearby galaxies: theory and observations') supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia. The Serbian station is the Astronomical Station Vidojevica (ASV) with the 60-cm ASV telescope (and from this year, the 1.4-m ASV one). This research was supported partly by funds of the project RD-08-81 of the Shumen University.

Published
2017

11. Unveiling the nature of the γ-ray emitting active galactic nucleus PKS 0521−36

Author

C. M. Raiteri, Giuseppe Malaguti, M. F. Aller, Elena Pian, Filippo D'Ammando, Hugh D. Aller, Paola Grandi, Monica Orienti, G. Tosti, Gabriele Ghisellini, Eleonora Torresi, Mark Gurwell, Marcello Giroletti, Fabrizio Tavecchio, D'Ammando, F., Orienti, M., Tavecchio, F., Ghisellini, G., Torresi, E., Giroletti, M., Raiteri, C. M., Grandi, P., Aller, M., Aller, H., Gurwell, M. A., Malaguti, G., Pian, E., and Tosti, G.

Subjects
Physics, Active galactic nucleus, Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Quasar, Galaxies: active, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, gamma-rays: general, galaxies: active, galaxies: individual: PKS 0521−36, galaxies: nuclei, quasars: general, gamma-rays: galaxies, gamma-rays: general, Galaxies: individual: PKS0521-36, Viewing angle, Radio spectrum, Galaxies: nuclei, Gamma-rays: galaxies, Quasars: general, Space and Planetary Science, Spectral energy distribution, Emission spectrum, Blazar
Abstract

PKS 0521-36 is an active galactic nucleus (AGN) with uncertain classification. We investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spectrum radio quasars (SSRQ). On pc-scales PKS 0521-36 shows a knotty structure similar to misaligned AGN. The core dominance and the γ-ray properties are similar to those estimated for other SSRQ and BLRG detected in γ-rays, suggesting an intermediate viewing angle with respect to the observer. In this context the flaring activity detected from this source by Fermi-Large Area Telescope between 2010 June and 2012 February is very intriguing. We discuss the γ-ray emission of this source in the framework of the structured jet scenario, comparing the spectral energy distribution (SED) of the flaring state in 2010 June with that of a low state. We present three alternative models corresponding to three different choices of the viewing angles θv = 6°, 15°, and 20°. We obtain a good fit for the first two cases, but the SED obtained with θv = 15° if observed at a small angle does not resemble that of a typical blazar since the synchrotron emission should dominate by a large factor (̃100) the inverse Compton component. This suggests that a viewing angle between 6° and 15° is preferred, with the rapid variability observed during γ-ray flares favouring a smaller angle. However, we cannot rule out that PKS 0521-36 is the misaligned counterpart of a synchrotron-dominated blazar.

Published
2015
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12. Gamma-ray blazars: The view from AGILE

Author

Filippo D'Ammando, F. Longo, P. Romano, Marco Tavani, Andrea Bulgarelli, S. Vercellone, Luigi Pacciani, C. M. Raiteri, Stefano Covino, V. Vittorini, E. Striani, Hans A. Krimm, A. W. Chen, M. Villata, G. Pucella, I. Donnarumma, A. Giuliani, F., D'Ammando, A., Bulgarelli, A. W., Chen, I., Donnarumma, A., Giuliani, Longo, Francesco, L., Pacciani, G., Pucella, E., Striani, M., Tavani, S., Vercellone, V., Vittorini, S., Covino, H. A., Krimm, C. M., Raiteri, P., Romano, M., Villata, DAmmando F, Bulgarelli A, Chen AW, Donnarumma I, Giuliani A, Longo F, Pacciani L, Pucella G, Striani E, Tavani M, Vercellone S, Vittorini V, Covino S, Krimm HA, Raiteri CM, Romano P, and Villata M

Subjects
Atmospheric Science, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, FOS: Physical sciences, Aerospace Engineering, Astrophysics, High Energy Gamma-ray Astronomy, law.invention, Telescope, Gamma-ray sources, Quasars, Active galactic nuclei, BL Lac objects, Blazars, law, MAGIC (telescope), Blazar, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Detector, Gamma ray, Astronomy, Active Galactic Nuclei, Astronomy and Astrophysics, Quasar, Geophysics, Space and Planetary Science, General Earth and Planetary Sciences, Satellite, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

During the first 3 years of operation the Gamma-Ray Imaging Detector onboard the AGILE satellite detected several blazars in a high gamma-ray activity: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421, PKS 0537-441 and 4C +21.35. Thanks to the rapid dissemination of our alerts, we were able to obtain multiwavelength data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, and ARGO as well as radio-to-optical coverage by means of the GASP Project of the WEBT and the REM Telescope. This large multifrequency coverage gave us the opportunity to study the variability correlations between the emission at different frequencies and to obtain simultaneous spectral energy distributions of these sources from radio to gamma-ray energy bands, investigating the different mechanisms responsible for their emission and uncovering in some cases a more complex behaviour with respect to the standard models. We present a review of the most interesting AGILE results on these gamma-ray blazars and their multifrequency data., Comment: 25 pages, 10 figures, accepted for publication on Advances in Space Research. Talk presented at the 38th COSPAR Scientific Assembly (Bremen, Germany; July 18-25, 2010)

Published
2011
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13. SBS 0846+513: a new γ-ray-emitting narrow-line Seyfert 1 galaxy

Author

Marcello Giroletti, A. C. S. Readhead, Walter Max-Moerbeck, Justin D. Finke, M. Orienti, L. Stawarz, Emmanouil Angelakis, L. Fuhrmann, C. M. Raiteri, Filippo D'Ammando, J. L. Richards, J. S. Perkins, D. Donato, and Talvikki Hovatta

Subjects
Physics, Superluminal motion, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy and Astrophysics, Quasar, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Luminosity, Black hole, Space and Planetary Science, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Fermi Gamma-ray Space Telescope
Abstract

We report Fermi-LAT observations of the radio-loud AGN SBS 0846+513 (z=0.5835), optically classified as a Narrow-Line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at gamma-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular a strong gamma-ray flare was observed in 2011 June reaching an isotropic gamma-ray luminosity (0.1-300 GeV) of 1.0x10^48 erg/s, comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in gamma rays. An apparent superluminal velocity of (8.2+/-1.5)c in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

Published
2012
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14. The optical spectrum of PKS 1222+216 and its black hole mass

Author

Emanuele Paolo Farina, C. M. Raiteri, Roberto Decarli, Renato Falomo, and Aldo Treves

Subjects
Physics, Solar mass, Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Virial theorem, Luminosity, Black hole, Space and Planetary Science, Thermal, Blazar, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

We investigate the optical spectral properties of the blazar PKS 1222+216 during a period of 3 years. While the continuum is highly variable the broad line emission is practically constant. This supports a scenario in which the broad line region is not affected by jet continuum variations. We thus infer the thermal component of the continuum from the line luminosity and we show that it is comparable with the continuum level observed during the phases of minimum optical activity. The mass of the black hole is estimated through the virial method from the FWHM of MgII, Hbeta, and Halpha broad lines and from the thermal continuum luminosity. This yields a consistent black hole mass value of 6x10^8 solar masses.

Published
2012
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15. Broad band spectral energy distribution studies of Fermi bright blazars

Author

C. M. Raiteri, Lars Fuhrmann, C. Monte, E. Cavazzuti, Dario Gasparrini, M. Perri, S. Rainò, Emmanouil Angelakis, Paolo Giommi, M. Villata, and Joseph L. Richards

Subjects
Physics, Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, Astrophysics, Galaxy, Spectral line, law.invention, Telescope, Spitzer Space Telescope, law, Spectral energy distribution, Blazar, Instrumentation, Fermi Gamma-ray Space Telescope
Abstract

The Fermi Gamma-ray Space Telescope was successfully launched on June 11, 2008 and has already opened a new era for gamma-ray astronomy. The Large Area Telescope (LAT), the main instrument on board Fermi, presents a significant improvement in sensitivity over its predecessor EGRET, due to its large field of view and effective area, combined with its excellent timing capabilities. The preliminary results of the Spectral Energy Distribution Analysis performed on a sample of bright blazars are presented. For this study, the data from the first three months of data collection of Fermi have been used. The analysis is extended down to radio, mm, near-IR, optical, UV and X-ray bands and up to TeV energies based on unprecedented sample of simultaneous multi-wavelength observations by GASP-WEBT.

Published
2011
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16. Color variations of the blazar 3C 454.3 in 2004–2006

Author

C. A. Gomez, A. Sillanpää, E. I. Hagen-Thorn, M. Villata, L. V. Larionova, L. O. Takalo, Svetlana G. Jorstad, C. M. Raiteri, Vladimir A. Hagen-Thorn, A. A. Arkharov, N. V. Efimova, and Valeri M. Larionov

Subjects
Physics, Brightness, Extinction (astronomy), Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, Power law, Synchrotron, law.invention, Space and Planetary Science, law, Observatory, Spectral energy distribution, Blazar
Abstract

We present an analysis of multicolor (U BV RI JH K) observations of the blazar 3C 454.3 made in 2004–2006. We used the light curves compiled at the Turin Observatory from coordinated observations in the framework of the WEBT program. We consider color variations in two time intervals, when an unprecedented strong outburst occurred (2004–2005), and when the object was in a post-eruptive state and a low-amplitude brightness increase was observed (2006). The spectral energy distribution (SED) of the variable component remained the same within each of these intervals, but differed between them. In both cases, this SED followed a power law after correction for extinction, suggesting the variable component has a synchrotron nature. We conclude that the variations in the optical and IR were due to the same variable source. The object’s unusual color behavior (the brighter, the redder) was due to an increasing contribution from a variable component that was redder than the constant component (big blue bump).

Published
2009
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17. Peculiar emission from the new VHE gamma-ray source H1722+119

Author

Antonio Stamerra, C. M. Raiteri, M. Villata, Omar M. Kurtanidze, F. D'Ammando, F. Verrecchia, and Tomislav Terzić

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Owens Valley Radio Observatory, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, Telescope, Crab Nebula, Space and Planetary Science, law, Spectral energy distribution, MAGIC (telescope), Blazar, BL Lac object, Fermi Gamma-ray Space Telescope
Abstract

The BL Lac object H1722+119 was observed in the very-high energy band (VHE, E > 100 GeV) by the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes between 2013 May 17 and 22, following a state of high activity in the optical band measured by the KVA (Kungliga Vetenskapsakademien) telescope. Integrating 12.5 h of observation, the source was detected with a statistical significance of 5.9 sigma, with measured flux of f = (6.3 ± 1.6) × 10−12 ph cm-2 s−1 above 150 GeV, corresponding to (2.0 ± 0.5) per cent of the Crab Nebula flux in the same energy range. Contemporaneous observations were performed by the LAT (Large Area Telescope) on board the Fermi satellite in the high energy range (HE, 100 MeV < E < 100 GeV), by instruments on board the Swift satellite in the UV and X-ray region and by the OVRO (Owens Valley Radio Observatory) telescope in the radio band, allowing us to build a quasi simultaneous multi-wavelength SED (spectral energy distribution). An unexpected feature in the ∼ 3x1014 - 1018 Hz frequency range of the SED was identified. A possible explanation using an inhomogeneous helical jet synchrotron self-Compton model is suggested. The combination of HE and VHE gamma-ray observations, and the expected imprint of the extragalactic background absorption, allowed us to set a constraint on the redshift of this blazar to be z = 0.34 ± 0.15. No significant temporal variability of the flux in the HE and VHE bands was found. Contemporaneous data from the KVA and the OVRO telescopes show variable flux in optical and radio wavebands, respectively, although with different patterns.

Published
2016
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18. 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
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19. Looking for the least luminous BL Lacertae objects

Author

Alessandro Capetti, C. M. Raiteri, and ITA

Subjects
Physics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Among active galactic nuclei, BL Lac objects show extreme properties that have been interpreted as the effect of relativistic beaming on the emission from a plasma jet oriented close to the line of sight. The Doppler amplification of the jet emission makes them ideal targets for studying jet physics. In particular, low-power BL Lacs (LPBL) are very interesting because they probe the jet formation and emission processes at the lowest levels of accretion. However, they are difficult to identify since their emission is swamped by the radiation from the host galaxy in most observing bands. In this paper we propose a new LPBL selection method based on the mid-infrared emission, in addition to the traditional optical indices. We considered the radio-selected sample of Best & Heckman (2012, MNRAS, 421, 1569) and cross-matched it with the WISE all-sky survey. In a new diagnostic plane including the W2-W3 color and the Dn(4000) index, LPBL are located in a region scarcely populated by other sources. By filtering objects with small emission line equivalent width, we isolated 36 LPBL candidates up to redshift 0.15. Their radio luminosity at 1.4 GHz spans the range log Lr = 39.2-41.5 [erg s-1]. Considering the completeness of our sample, we analyzed the BL Lac luminosity function (RLF), finding a dramatic paucity of LPBL with respect to the extrapolation of the RLF toward low power. This requires a break in the RLF located at log Lr ~ 40.6 [erg s-1]. The consequent peak in the BL Lacs number density is possibly the manifestation of a minimum power required to launch a relativistic jet.

Published
2015
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20. Multiwavelength behaviour of the blazar OJ 248 from radio to gamma-rays

Author

M. I. Carnerero, Sofia O. Kurtanidze, J. A. Acosta-Pulido, E. N. Kopatskaya, Paolo Leto, C. S. Lin, A. B. Grinon-Marin, Sol N. Molina, D. A. Morozova, H. C. Lin, R. Bachev, Neelam Panwar, A. I. Manilla-Robles, M. Orienti, Valeri M. Larionov, Marcello Giroletti, J. L. Gomez, P. A. González-Morales, Antoniya Valcheva, Carolina Casadio, Anne Lähteenmäki, Helmut Wiesemeyer, Uwe Bach, Goran Damljanović, Corrado Trigilio, Y. T. Metodieva, D. O. Mirzaqulov, Sunay Ibryamov, Elena G. Larionova, A. Bueno Bueno, T. S. Grishina, H. Y. Hsiao, V. Ramakrishnan, G. Umana, D. Carosati, Wen Ping Chen, Arkady A. Arkharov, V. Bozhilov, Ivan Agudo, Mark Gurwell, A. Pastor Yabar, I. M. McHardy, David Hiriart, Carla Buemi, Manasvita Joshi, A. Strigachev, Alan P. Marscher, S. G. Jorstad, A. Di Paola, Lorand A. Sigua, L. V. Larionova, M. J. Arévalo, N. V. Efimova, D. Blinov, Erika Benítez, C. M. Raiteri, Brian W. Taylor, Omar M. Kurtanidze, I. Puerto Giménez, Evgeni Ovcharov, Yu. V. Troitskaya, M. G. Nikolashvili, Sergio Velasco, Ann E. Wehrle, A. A. Mokrushina, Paul S. Smith, M. Villata, Ivan S. Troitsky, Sh. A. Ehgamberdiev, Merja Tornikoski, M. Rossini, G. M. Richter, Filippo D'Ammando, C. Lázaro, O. Vince, Carnerero MI, Raiteri CM, Villata M, Acosta-Pulido JA, DAmmando F, Smith PS, Larionov VM, Agudo I, Arevalo MJ, Arkharov AA, Bach U, Bachev R, Benitez E, Blinov DA, Bozhilov V, Buemi CS, Bueno AB, Carosati D, Casadio C, Chen WP, Damljanovic G, Di Paola A, Efimova NV, Ehgamberdiev SA, Giroletti M, Gomez JL, Gonzalez-Morales PA, Grinon-Marin AB, Grishina TS, Gurwell MA, Hiriart D, Hsiao HY, Ibryamov S, Jorstad SG, Joshi M, Kopatskaya EN, Kurtanidze OM, Kurtanidze SO, Lahteenmaki A, Larionova EG, Larionova LV, Lazaro C, Leto P, Lin CS, Lin HC, Manilla-Robles AI, Marscher AP, McHardy IM, Metodieva Y, Mirzaqulov DO, Mokrushina AA, Molina SN, Morozova DA, Nikolashvili MG, Orienti M, Ovcharov E, Panwar N, Yabar AP, Gimenez IP, Ramakrishnan V, Richter GM, Rossini M, Sigua LA, Strigachev A, Taylor B, Tornikoski M, Trigilio C, Troitskaya YV, Troitsky IS, Umana G, Valcheva A, Velasco S, Vince O, Wehrle AE, Wiesemeyer H, Anne Lähteenmäki Group, Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
active [Galaxies], Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, ta221, galaxies: active, ta1171, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, Observatory, law, quasars: general, Emission spectrum, Blazar, ta216, Physics, individual: OJ 248 [Quasars], ta115, ta213, ta114, Linear polarization, quasars: individual: OJ 248, Astronomy, Astronomy and Astrophysics, general [Quasars], galaxies: active, galaxies: jets, quasars: general, quasars: individual: OJ 248, galaxies: jets, Light curve, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, jets [Galaxies], Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract

We present an analysis of the multiwavelength behaviour of the blazar OJ 248 at z = 0.939 in the period 2006-2013. We use low-energy data (optical, near-infrared, and radio) obtained by 21 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as data from the Swift (optical-UV and X-rays) and Fermi (gamma-rays) satellites, to study flux and spectral variability and correlations among emissions in different bands. We take into account the effect of absorption by the Damped Lyman Alpha intervening system at z = 0.525. Two major outbursts were observed in 2006-2007 and in 2012-2013 at optical and near-IR wavelengths, while in the high-frequency radio light curves prominent radio outbursts are visible peaking at the end of 2010 and beginning of 2013, revealing a complex radio-optical correlation. Cross-correlation analysis suggests a delay of the optical variations after the gamma-ray ones of about a month, which is a peculiar behaviour in blazars. We also analyse optical polarimetric and spectroscopic data. The average polarization percentage P is less than 3 per cent, but it reaches about 19 per cent during the early stage of the 2012-2013 outburst. A vague correlation of P with brightness is observed. There is no preferred electric vector polarisation angle and during the outburst the linear polarization vector shows wide rotations in both directions, suggesting a complex behaviour or structure of the jet and possible turbulence. The analysis of 140 optical spectra acquired at the Steward Observatory reveals a strong Mg II broad emission line with an essentially stable flux of 6.2 e-15 erg cm-2 s-1 and a full width at half-maximum of 2053 km s-1., Comment: 16 pages, 20 figures, 2 tables, in press for MNRAS

Published
2015

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