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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. Multiwavelength periodicity search in a sample of γ-ray bright blazars

Author: J Otero-Santos, P Peñil, J A Acosta-Pulido, J Becerra González, C M Raiteri, M I Carnerero, and M Villata
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the results of a long-term periodicity search in a sample of $\gamma$-ray blazars within a multiwavelength context. These blazars have been selected from the Steward Observatory sample as part of its optical monitoring program between 2008 and 2018. We study 15 sources with a temporal coverage in their optical total and polarized emission sufficiently large ($>9$ years) to perform a reliable long-term periodicity analysis. We collect data from several observatories to extend the coverage, enabling the search of longer periods. In addition, data are also gathered in the high-energy ($E>100$ MeV) $\gamma$-ray band from the $\textit{Fermi}$ Large Area Telescope; and in the 15-GHz radio band from the Owens Valley Radio Observatory. We identify 5 promising candidates to host quasi-periodic emission, AO 0235+164, PKS 1222+216, Mrk 501, BL Lacertae and 1ES 2344+514 with periods in one or more bands and statistical significances $\sim$3$\sigma$ after trial factor correction. AO 0235+164 shows a period of $\sim$8.2 years in the R band; PKS 1222+216 has a quasi-periodic modulation in its total and polarized optical emission of $\sim$1.6 years; Mrk 501 displays a $\sim$5-year quasi-periodicity in optical and radio wavelengths; BL Lacertae presents a period of $\sim$1.8 years in its polarized emission; and 1ES 2344+514 shows a hint of a $\sim$5.5-year period in its optical R band. We interpret these results in the framework of the most common models and scenarios, namely the presence of a binary supermassive black hole system; or geometrical effects like helical or precessing jets., Comment: Accepted for publication in MNRAS
Published: 2022
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9. 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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10. Long-term Swift and Mets\'ahovi monitoring of SDSS J164100.10+345452.7 reveals multi-wavelength correlated variability

Author: P. Romano, A. Lähteenmäki, S. Vercellone, L. Foschini, M. Berton, C. M. Raiteri, V. Braito, S. Ciroi, E. Järvelä, S. Baitieri, I. Varglund, M. Tornikoski, S. Suutarinen, Osservatorio Astronomico di Brera, Department of Electronics and Nanoengineering, European Southern Observatory Santiago, National Institute for Astrophysics, University of Padova, Urbanización Villafranca Del Castillo, Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), individual: SDSS J164100.10+345452.7 [Galaxies], Seyfert [Galaxies], active [Galaxies], Space and Planetary Science, FOS: Physical sciences, individuals: SDSS J164100.10+345452.7 [X-rays], Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the first multi-wavelength Swift monitoring campaign performed on SDSS J164100.10+345452.7, a nearby narrow-line Seyfert 1 galaxy formerly known as radio quiet which was recently detected both in the radio (at 37 GHz) and in the $\gamma$-rays, which hints at the presence of a relativistic jet. During our 20-month Swift campaign, while pursuing the primary goal of assessing the baseline optical/UV and X-ray properties of J1641, we caught two radio flaring episodes, one each year. Our strictly simultaneous multi-wavelength data closely match the radio flare and allow us to unambiguously link the jetted radio emission of J1641. Indeed, for the X-ray spectra preceding and following the radio flare a simple absorbed power-law model is not an adequate description, and an extra absorption component is required. The average spectrum of J1641 can be best described by an absorbed power law model with a photon index $\Gamma=1.93\pm0.12$, modified by a partially covering neutral absorber with a covering fraction $f=0.91_{-0.03}^{+0.02}$. On the contrary, the X-ray spectrum closest to the radio flare does not require such extra absorber and is much harder ($\Gamma_{\rm flare} \sim 0.7\pm0.4$), thus implying the emergence of a further, harder spectral component. We interpret this as the jet emission emerging from a gap in the absorber. The fractional variability we derive in the optical/UV and X-ray bands are found to be lower than the typical values reported in the literature, since our observations of J1641 are dominated by the source being in a low state. Under the assumption that the origin of the 37 GHz radio flare is the emergence of a jet from an obscuring screen also observed in the X-rays, the derived total jet power is $P^{\rm tot}_{\rm jet}=3.5\times10^{42}$ erg s$^{-1}$, comparable to the lowest measured in the literature. [Abridged], Comment: Accepted for publication in Astronomy and Astrophysics (13 pages, 4 figures, 8 tables)
Published: 2023

11. 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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12. Gaia Data Release 3: The first Gaia catalogue of variable AGN

Author: M. I. Carnerero, C. M. Raiteri, L. Rimoldini, D. Busonero, E. Licata, N. Mowlavi, I. Lecoeur-Taïbi, M. Audard, B. Holl, P. Gavras, K. Nienartowicz, G. Jevardat de Fombelle, R. Carballo, G. Clementini, L. Delchambre, S. Klioner, M.G. Lattanzi, and L. Eyer
Subjects: Space and Planetary Science, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: One of the novelties of the Gaia-DR3 with respect to the previous data releases is the publication of the multiband light curves of about 1 million AGN. The goal of this work was the creation of a catalogue of variable AGN, whose selection was based on Gaia data only. We first present the implementation of the methods to estimate the variability parameters into a specific object study module for AGN. Then we describe the selection procedure that led to the definition of the high-purity variable AGN sample and analyse the properties of the selected sources. We started from a sample of millions of sources, which were identified as AGN candidates by 11 different classifiers based on variability processing. Because the focus was on the variability properties, we first defined some pre-requisites in terms of number of data points and mandatory variability parameters. Then a series of filters was applied using only Gaia data and the Gaia Celestial Reference Frame 3 (Gaia-CRF3) sample as a reference.The resulting Gaia AGN variable sample, named GLEAN, contains about 872000 objects, more than 21000 of which are new identifications. We checked the presence of contaminants by cross-matching the selected sources with a variety of galaxies and stellar catalogues. The completeness of GLEAN with respect to the variable AGN in the last Sloan Digital Sky Survey quasar catalogue is about 47%, while that based on the variable AGN of the Gaia-CRF3 sample is around 51%. From both a comparison with other AGN catalogues and an investigation of possible contaminants, we conclude that purity can be expected to be above 95%. Multiwavelength properties of these sources are investigated. In particular, we estimate that about 4% of them are radio-loud. We finally explore the possibility to evaluate the time lags between the flux variations of the multiple images of strongly lensed quasars, and show one case., Comment: 19 pages, 31 figures, 2 table. This paper is part of Gaia Data Release 3 (DR3). In press for A&A
Published: 2022

13. Gaia Early Data Release 3 The Gaia Catalogue of Nearby Stars

Author: Zoltan Balog, G. Tauran, Vincenzo Ripepi, Gerry Gilmore, M. Barros, Łukasz Wyrzykowski, Alberto Cellino, E. Poggio, P. Gavras, Simchon Faigler, Marc Audard, C. Nicolas, M. Vaillant, A. Mora, Paolo Tanga, Silvio Leccia, Despina Hatzidimitriou, A. Dapergolas, Eva Sciacca, Alberto Krone-Martins, N. Cheek, M. Hauser, Ulrike Heiter, S. Managau, L. Rohrbasser, Mathias Schultheis, E. Utrilla, Minia Manteiga, Marcella Marconi, Xavier Luri, F. De Angeli, Shay Zucker, Paolo Giacobbe, J. Juaristi Campillo, H. I. Siddiqui, J. Torra, F. X. Pineau, Roy Gomel, Thierry Morel, T. Cornez, Eric Gosset, Mario Gai, Jose M Hernandez, G. Giuffrida, A. de Torres, Laszlo Szabados, S. Ragaini, E. van Dillen, D. Semeux, Leanne P. Guy, R. Drimmel, L. M. Sarro, S. Voutsinas, Johannes Sahlmann, Damien Ségransan, S. Liao, Derek W. Morris, Jan Rybizki, André Moitinho, T. Roegiers, Bengt Edvardsson, Tristan Cantat-Gaudin, Martin Altmann, C. Turon, Laurent Chemin, K. Janßen, D. Garabato, Alejandra Recio-Blanco, Michał Pawlak, Lorenzo Rimoldini, Sergei A. Klioner, F. Torra, Carine Babusiaux, Alfred Castro-Ginard, G. Plum, Mariateresa Crosta, Iain A. Steele, A. Yoldas, Alex Lobel, J.-L. Bassilana, Harry Enke, Rosanna Sordo, Francesca Fragkoudi, F. De Luise, M. Bernet, Alessandro Sozzetti, M. Kontizas, Roberto Molinaro, C. Diener, S. Regibo, D. Barbato, T. Pauwels, R. E. de Souza, C. Fabricius, D. Souami, L. Martin Polo, M. Ramos-Lerate, Douglas J. Marshall, A. G. Butkevich, P. Madrero Pardo, P. Re Fiorentin, J. F. Le Campion, Jérôme Berthier, N. Tonello, Ummi Abbas, Y. Lebreton, M. Biermann, D. Munoz, N. Brouillet, David Teyssier, O. Vanel, P. A. Palicio, A. Jean-Antoine Piccolo, A. F. Lanza, Jesus Salgado, E. del Pozo, Antti Penttilä, R. Geyer, Ramachrisna Teixeira, L. Chaoul, Mike Smith, Rossella Cancelliere, J. M. Martín-Fleitas, D. Baines, M. Romero-Gómez, E. Anglada Varela, E. Livanou, X. Peñalosa Esteller, S. Diakite, Alberto Vecchiato, Thomas Wevers, Daniel Hestroffer, Sebastian L. Hidalgo, M. David, Angela Bragaglia, J. De Ridder, Mark Taylor, Roberto Morbidelli, A. Sagristà Sellés, Nigel Hambly, Arnaud Siebert, R. L. Smart, P. Burgess, Y. Le Fustec, Alessandro Bressan, H. Steidelmüller, Alberto Riva, H. E. Huckle, Morgan Fouesneau, N. Bauchet, P. Osborne, S. Marinoni, Krzysztof A. Rybicki, A. Masip, Laia Casamiquela, R. Messineo, A. Garofalo, Antonella Vallenari, R. Mor, Sahar Shahaf, P. de Laverny, G. Sadowski, Peter G. Jonker, A. Kochoska, F. Taris, A. F. Mulone, M. Ajaj, C. Ducourant, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Tatiana Muraveva, W. van Reeven, P. Sartoretti, Jordi Portell, Andreas Korn, E. Salguero, Ana Ulla, P. Di Matteo, Coryn A. L. Bailer-Jones, J. Bakker, F. Riclet, G. Altavilla, Ulrich Bastian, P. Esquej, R. Buzzi, M. Segol, A. C. Lanzafame, L. Balaguer-Núñez, Beatrice Bucciarelli, C. Panem, E. Balbinot, T. Carlucci, Davide Massari, P. de Teodoro, Sébastien Lambert, M. I. Carnerero, Amina Helmi, F. Solitro, C. Robin, Carlos Dafonte, Tsevi Mazeh, A. Panahi, C. Fabre, Sergi Blanco-Cuaresma, Deborah Busonero, Maroussia Roelens, O. Marchal, Tomaz Zwitter, B. Holl, G. Holland, William Thuillot, Michael Davidson, E. Licata, Michele Bellazzini, Teresa Antoja, E. Szegedi-Elek, Francesca Figueras, Eric Slezak, Sergio Messina, N. Samaras, E. Poujoulet, Mark Cropper, A. Burlacu, R. Blomme, Elmé Breedt, Annie C. Robin, H. E. Delgado, Z. Kostrzewa-Rutkowska, Georges Kordopatis, Conny Aerts, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, Grigori Fedorets, Maria Süveges, F. Crifo, J. Guiraud, D. Eappachen, K. Kruszyńska, Gisella Clementini, P. Yvard, Carme Jordi, L. Bramante, G. Busso, P. David, E. Fraile, Ugo Becciani, A. Lorca, Sanjeev Khanna, Alex Bombrun, Isabella Pagano, C. Dolding, A. M. Piersimoni, Paolo Montegriffo, A. Abreu Aramburu, Anthony G. A. Brown, Simon Hodgkin, Ennio Poretti, M. Fabrizio, I. Gonzalez-Santamaria, N. A. Walton, P. Panuzzo, Benoit Carry, Raphael Guerra, J. J. González-Vidal, T. Lebzelter, Nami Mowlavi, C. Barache, M. M. S. Marcos Santos, S. Cowell, Marco Castellani, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, N. Leclerc, S. Bartolomé, J. Álvarez Cid-Fuentes, F. van Leeuwen, S. Bouquillon, Uwe Lammers, D. W. Evans, L. Eyer, M. van Leeuwen, A. Guerrier, J. González-Núñez, H. E. P. Lindstrøm, Miguel García-Torres, Ilaria Musella, L. Palaversa, W. Roux, W. Löffler, J.-B. Delisle, Dimitri Pourbaix, Timo Prusti, J. Osinde, M. Riello, G. Orrù, C. Crowley, Alessandra Mastrobuono-Battisti, Hector Canovas, D. L. Harrison, Y. Lasne, E. F. del Peloso, Laurent Galluccio, N. Hładczuk, T. Boch, Martin A. Barstow, László Molnár, Aldo Dell'Oro, C. Pagani, Krzysztof Nienartowicz, Stefano Bertone, Patrick Charlot, Eduard Masana, Elisabetta Caffau, N. Robichon, Luciana Bianchi, Federica Spoto, Felix Franke, J. L. Halbwachs, R. Gutiérrez-Sánchez, L. Pulone, Yassine Damerdji, Frédéric Arenou, Richard I. Anderson, Elena Pancino, David Hobbs, P. Castro Sampol, Yves Fremat, Pierre Kervella, C. Zurbach, Sofia Randich, Robert G. Mann, J. C. Segovia, Diego Bossini, D. Katz, Nicholas Rowell, P. Ramos, E. Racero, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Kevin Benson, Christos Siopis, J. Souchay, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Pierre Fernique, Céline Reylé, F. Pailler, Stefan Jordan, J. H. J. de Bruijne, C. A. Stephenson, E. Gerlach, Elisa Distefano, Karri Muinonen, Y. Viala, H. Zhao, L. Siltala, C. P. Murphy, Maria-Rosa L. Cioni, Andrea Chiavassa, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, Federico Marocco, Nicoletta Sanna, Alexey Mints, Juan Zorec, Ángel Gómez, I. Bellas-Velidis, M. G. Lattanzi, C. M. Raiteri, E. Brugaletta, Mikael Granvik, O. L. Creevey, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Jon Marchant, Monica Rainer, Alessandro Spagna, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, C. Fouron, S. Girona, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, Generalitat de Catalunya, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Mésocentre de calcul (MESOCENTRE), Université de Franche-Comté (UFC), Centre de Données Astronomiques de Strasbourg, Partenaires INRAE, Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), THALES, Université de Namur [Namur] (UNamur), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), THALES [France], Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universidad de Cantabria, Gaia Collaboration, Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Astronomy, and ITA
Subjects: trigonometric parallaxes, Solar neighborhood, Stars: luminosity function, mass function, Astronomy, Astrophysics, 01 natural sciences, luminosity function, mass function [Stars], Astronomi, astrofysik och kosmologi, luminosity: mass function [Stars], Astronomy, Astrophysics and Cosmology, MAIN-SEQUENCE, Hertzsprung-Russell-diagram, 010303 astronomy & astrophysics, Stars:low-mass brown-dwarfs, wide binaries, Physics, education.field_of_study, north galactic pole, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, BROWN DWARF, Astrophysics - Solar and Stellar Astrophysics, mass function, NORTH GALACTIC POLE, Physical Sciences, symbols, CIRCULAR-VELOCITY CURVE, Halo, astro-ph.SR, Hertzsprung–Russell diagram, stars: luminosity function, astro-ph.GA, Posterior probability, Population, main-sequence, Luminosity-Function, FOS: Physical sciences, Mass-Function, Astronomy & Astrophysics, Computer Science::Digital Libraries, Photometry (optics), DWARF LUMINOSITY-FUNCTION, dwarf luminosity-function, sky-survey, symbols.namesake, Settore FIS/05 - Astronomia e Astrofisica, luminosity function [stars], low-mass [Stars], 0103 physical sciences, Stars: luminosity: mass function, Stars: low-mass, WHITE-DWARFS, education, Solar and Stellar Astrophysics (astro-ph.SR), brown dwarf, catalogs, astrometry, Hertzsprung-Russell and C-M diagrams, stars: low-mass, solar neighborhood, Astrophysics - Astrophysics of Galaxies, SKY-SURVEY, white-dwarfs, Science & Technology, 010308 nuclear & particles physics, Luminosity function, White dwarf, TRIGONOMETRIC PARALLAXES, Astronomy and Astrophysics, Low-mass, 115 Astronomy, Space science, WIDE BINARIES, Stars, Physics::History of Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), solar-neighborhood, Catalogs, circular-velocity curve, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use., Methods. Theselection of objects within 100 pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100 pc is included in the catalogue., Results. We have produced a catalogue of 331 312 objects that we estimate contains at least 92% of stars of stellar type M9 within 100 pc of the Sun. We estimate that 9% of the stars in this catalogue probably lie outside 100 pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun., Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.
Published: 2021
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14. A statistical study of the optical spectral variability in gamma-ray blazars

Author: J Otero-Santos, J A Acosta-Pulido, J Becerra González, A Luashvili, N Castro Segura, O González-Martín, C M Raiteri, and M I Carnerero
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract: Blazars optical emission is generally dominated by relativistic jets, although the host galaxy, accretion disk and broad line region (BLR) may also contribute significantly. Disentangling their contributions has been challenging for years due to the dominance of the jet. To quantify the contributions to the spectral variability, we use the statistical technique for dimensionality reduction Non-Negative Matrix Factorization on a spectroscopic data set of 26 $\gamma$-ray blazars. This technique allows to model large numbers of spectra in terms of a reduced number of components.We use a priori knowledge to obtain components associated to meaningful physical processes. The sources are classified according to their optical spectrum as host-galaxy dominated BL Lac objects (BL Lacs), BL Lacs, or Flat Spectrum Radio Quasars (FSRQs). Host-galaxy sources show less variability, as expected, and bluer-when-brighter trends, as the other BL Lacs. For FSRQs, more complicated colour-flux behaviours are observed: redder-when-brighter for low states saturating above a certain level and, in some cases, turning to bluer-when-brighter. We are able to reproduce the variability observed during 10 years using only 2 to 4 components, depending on the type. The simplest scenario corresponds to host-galaxy blazars, whose spectra are reconstructed using the stellar population and a power law for the jet. BL Lac spectra are reproduced using from 2 to 4 power laws. Different components can be associated to acceleration/cooling processes taking place in the jet. The reconstruction of FSRQs also incorporates a QSO-like component to account for the BLR, plus a very steep power law, associated to the accretion disk., Comment: Accepted for publication in MNRAS
Published: 2022

15. Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017

Author: Katsuaki Asano, I. Jiménez, A. Fuentes, C. M. Raiteri, D. Dominis Prester, E. Molina, E. Colombo, Y. V. Troitskaya, Nikola Godinovic, Sidika Merve Colak, Jenni Jormanainen, Yuki Iwamura, Alessandra Lamastra, Lab Saha, Antoniya Valcheva, Sunay Ibryamov, Elena G. Larionova, B. De Lotto, Evgeni Ovcharov, D. Zarić, Kazuma Ishio, David A. Green, M. Villata, D. Horan, Givi N. Kimeridze, Alexander Hahn, S. Nozaki, M. Perri, Michael D. Joner, D. Neise, S. Loporchio, R. J. García López, Marcello Giroletti, Victor A. Acciari, V. Fallah Ramazani, Tomohiko Oka, Daniela Dorner, Narek Sahakyan, J. Kushida, M. Kopp, Lorenzo Bellizzi, Noah Biederbeck, Joseph Moody, M. Gaug, L. Schneider, A. López-Oramas, Daniel Morcuende, N. Rizzi, Jose Luis Contreras, G. Vanzo, Rodolfo Carosi, L. Maraschi, Andrés Baquero, M. I. Carnerero, R. Iotov, Mosè Mariotti, A. Paravac, John Hoang, Ashwani Pandey, Z. R. Weaver, Francesco Longo, F. D'Ammando, S. Paiano, Elina Lindfors, Moritz Hütten, J. Herrera, Koji Noda, Abelardo Moralejo, Laura Eisenberger, E. Moretti, Julian Sitarek, Marcos López-Moya, Wlodek Bednarek, L. Di Venere, Ashot Chilingarian, U. Barres de Almeida, Elisa Bernardini, I. Agudo, M. Feige, R. Z. Ivanidze, O. A. Merkulova, D. Depaoli, M. Spencer, Massimo Persic, J. van Scherpenberg, Pratik Majumdar, L. Kunkel, K. Nishijima, Stefano Ansoldi, Juan Cortina, Kai Phillip Schmidt, A. Berti, Riccardo Paoletti, Saverio Lombardi, Daniel Mazin, M. V. Fonseca, Damir Lelas, R. J. C. Vera, Sanae Inoue, Giacomo D'Amico, Dominik Baack, C. Perennes, A. A. Nikiforova, Yating Chai, Stefan Cikota, G. M. Madejski, A. Arbet Engels, Daniel Kerszberg, Manuel Artero, E. Do Souto Espiñeira, Tomislav Terzić, J. Becerra González, Martin Makariev, R. Mirzoyan, Yoshiki Ohtani, G. A. Borman, Pawel Gliwny, Jose Miguel Miranda, A. De Angelis, Vitaly Neustroev, Wara Chamani, Oscar Blanch, T. S. Grishina, Martin Will, M. Vazquez Acosta, Nicola Giglietto, L. V. Larionova, Lea Heckmann, Francesco Gabriele Saturni, Jorge Otero-Santos, R. A. Chigladze, M. Balbo, N. Marchili, D. Hadasch, P. G. Prada Moroni, A. A. Vasilyev, M. G. Nikolashvili, Jordi Delgado, V. Ramakrishnan, Christian Fruck, G. Busetto, Victoria Moreno, Luca Tosti, A. Rugliancich, C. Nigro, Marina Manganaro, Valeri M. Larionov, M. Balokovic, Manuel Delfino, A. Strigachev, J. M. Paredes, Manash R. Samal, Stefano Covino, I. Vovk, H. C. Lin, Ž. Bošnjak, Stefano Menchiari, Rumen Bachev, Marc Ribó, Dorota Sobczyńska, Carolin Wunderlich, Bernd Schleicher, M. Minev, Antonio Stamerra, Maria-Isabel Bernardos, I. S. Troitskiy, Merja Tornikoski, E. N. Kopatskaya, Shunsuke Sakurai, Camilla Maggio, Chiara Righi, F. Verrecchia, P. Temnikov, S. G. Jorstad, T. Schweizer, Hidetoshi Kubo, Lluis Font, A. Y. Lien, Toshiaki Inada, A. Scherbantin, Lorand A. Sigua, G. Maneva, Stefano Truzzi, B. Machado de Oliveira Fraga, V. Bozhilov, M. Palatiello, Alessandro Marchini, Chaitanya Priyadarshi, Alessia Spolon, Léa Jouvin, Konstancja Satalecka, Tomoki Saito, Giovanni Ceribella, Michele Doro, S. O. Kurtanidze, Carlo Vigorito, Pablo Peñil, D. Strom, Giacomo Bonnoli, Adrian Biland, Ana Babić, Alicia Fattorini, D. Hildebrand, Satoshi Fukami, G. Ferrara, Y. Kajiwara, Matteo Cerruti, P. Da Vela, Vassil Verguilov, Lovro Pavletić, C. Delgado Mendez, Emilia Järvelä, S. Mićanović, Sergey S. Savchenko, Ivica Puljak, M. Noethe, Simone Mender, Francesco Dazzi, V. Vitale, Manuela Mallamaci, Ivana Batković, F. Leone, M. I. Martínez, J. Rico, Alan P. Marscher, C. Lorey, S. Ventura, Tjark Miener, Anne Lähteenmäki, David Paneque, Masahiro Teshima, Jarred Gershon Green, Wrijupan Bhattacharyya, Kari Nilsson, R. Walter, M. Strzys, D. Reinhart, E. Zaharieva, Wen Ping Chen, Vitalii Sliusar, Jürgen Besenrieder, Francesco Giordano, Antonio Tutone, Thomas Bretz, J. Buss, Alok C. Gupta, Simona Righini, O. M. Kurtanidze, Ciro Bigongiari, O. Vince, D. Elsaesser, C. Leto, M. Garczarczyk, Sargis Gasparyan, J. Kania, Dario Hrupec, R. López-Coto, Wolfgang Rhode, I. Snidaric, D. A. Morozova, Vladimir A. Hagen-Thorn, Mitsunari Takahashi, J. A. Acosta-Pulido, E. Prandini, Marie Karjalainen, D. Miceli, Goran Damljanović, Evgeni Semkov, Alice Donini, L. A. Antonelli, J. A. Barrio, Y. Suda, D. Carosati, V. D'Elia, Fabrizio Tavecchio, A. C. Sadun, Tihomir Surić, C. Casadio, Karl Mannheim, Santiago Ubach, Y. Kobayashi, F. Di Pierro, European Commission, European Research Council, Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, Federal Ministry of Education and Research (Germany), German Research Foundation, Swiss National Science Foundation, Croatian Science Foundation, Ministry of Education, Science and Technological Development (Serbia), Bulgarian National Science Fund, National Aeronautics and Space Administration (US), Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Artero, M., Asano, K., Babi??, A., Baquero, A., Barres de Almeida, U., Barrio, J. A., Batkovi??, I., Becerra Gonz??lez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bo??njak, ??., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D???amico, G., D???elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espi??eira, E., Dominis Prester, D., Donini, A., Doro, M., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garc??a L??pez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovi??, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., H??tten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jim??nez, I., Jormanainen, J., Jouvin, L., Kajiwara, Y., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., L??pez-Coto, R., L??pez-Moya, M., L??pez-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Mart??nez, M., Mazin, D., Menchiari, S., Mender, S., Mi??anovi??, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavleti??, L., Pe??il, P., Perennes, C., Persic, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Rib??, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Schmidt, K., Schweizer, T., Sitarek, J., nidari??, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suri??, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzi??, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Zari??, D., Baack, D., Balbo, M., Biederbeck, N., Biland, A., Bretz, T., Buss, J., Dorner, D., Eisenberger, L., Elsaesser, D., Hildebrand, D., Iotov, R., Mannheim, K., Neise, D., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Sliusar, V., Walter, R., D???ammando, F., Horan, D., Lien, A. Y., Balokovi??, M., Madejski, G. M., Perri, M., Verrecchia, F., Leto, C., L??hteenm??ki, A., Tornikoski, M., Ramakrishnan, V., J??rvel??, E., Vera, R. J. C., Chamani, W., Villata, M., Raiteri, C. M., Gupta, A. C., Pandey, A., Fuentes, A., Agudo, I., Casadio, C., Semkov, E., Ibryamov, S., Marchini, A., Bachev, R., Strigachev, A., Ovcharov, E., Bozhilov, V., Valcheva, A., Zaharieva, E., Damljanovic, G., Vince, O., Larionov, V. M., Borman, G. A., Grishina, T. S., Hagen-Thorn, V. A., Kopatskaya, E. N., Larionova, E. G., Larionova, L. V., Morozova, D. A., Nikiforova, A. A., Savchenko, S. S., Troitskiy, I. S., Troitskaya, Y. V., Vasilyev, A. A., Merkulova, O. A., Chen, W. P., Samal, M., Lin, H. C., Moody, J. W., Sadun, A. C., Jorstad, S. G., Marscher, A. P., Weaver, Z. R., Feige, M., Kania, J., Kopp, M., Kunkel, L., Reinhart, D., Scherbantin, A., Schneider, L., Lorey, C., Acosta-Pulido, J. A., Carnerero, M. I., Carosati, D., Kurtanidze, S. O., Kurtanidze, O. M., Nikolashvili, M. G., Chigladze, R. A., Ivanidze, R. Z., Kimeridze, G. N., Sigua, L. A., Joner, M. D., Spencer, M., Giroletti, M., Marchili, N., Righini, S., Rizzi, N., Bonnoli, G., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), MAGIC, FACT, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University
Subjects: electron, PARTICLE-ACCELERATION, ELECTRON ACCELERATION, Radiation mechanisms: non-thermal, RAY, VHE [gamma ray], galaxies: active, BL Lacertae objects: individual: Mrk 421, radiation mechanisms: non-thermal, Electron, Astrophysics, GeV, 01 natural sciences, 7. Clean energy, LARGE-AREA TELESCOPE, law.invention, OBSERVATIONS, law, ultraviolet, optical, MAGIC (telescope), correlation [flux], 010303 astronomy & astrophysics, X-ray: flux, model: leptonic, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), BL-LACERTAE, individual: Mrk 421 [BL Lacertae objects], flux [X-ray], Gamma ray, flux: correlation, Galaxies: active, non-thermal [radiation mechanisms], Synchrotron, SWIFT OBSERVATIONS, active [galaxies], Spectral energy distribution, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, Lorentz, Flare, LOG-PARABOLIC SPECTRA, ACTIVE GALACTIC NUCLEI, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, radiation, mechanisms: non-thermal, LIGHT CURVES, X-RAY, MULTIWAVELENGTH, GLAST, leptonic [model], blazar, 0103 physical sciences, TeV, Blazar, 010308 nuclear & particles physics, Astronomy and Astrophysics, MAGIC, gamma ray: VHE, Space and Planetary Science, ddc:520, spectral, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract: Full list of authors: Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Arbet Engels, A.; Artero, M.; Asano, K.; Babić, A.; Baquero, A.; Barres de Almeida, U.; Barrio, J. A.; Batković, I.; Becerra González, J.; Bednarek, W.; Bellizzi, L.; Bernardini, E.; Bernardos, M.; Berti, A.; Besenrieder, J.; Bhattacharyya, W.; Bigongiari, C.; Blanch, O.; Bošnjak, Ž.; Busetto, G.; Carosi, R.; Ceribella, G.; Cerruti, M.; Chai, Y.; Chilingarian, A.; Cikota, S.; Colak, S. M.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; D'Amico, G.; D'Elia, V.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; Delfino, M.; Delgado, J.; Delgado Mendez, C.; Depaoli, D.; di Pierro, F.; di Venere, L.; Do Souto Espiñeira, E.; Dominis Prester, D.; Donini, A.; Doro, M.; Fallah Ramazani, V.; Fattorini, A.; Ferrara, G.; Fonseca, M. V.; Font, L.; Fruck, C.; Fukami, S.; García López, R. J.; Garczarczyk, M.; Gasparyan, S.; Gaug, M.; Giglietto, N.; Giordano, F.; Gliwny, P.; Godinović, N.; Green, J. G.; Green, D.; Hadasch, D.; Hahn, A.; Heckmann, L.; Herrera, J.; Hoang, J.; Hrupec, D.; Hütten, M.; Inada, T.; Inoue, S.; Ishio, K.; Iwamura, Y.; Jiménez, I.; Jormanainen, J.; Jouvin, L.; Kajiwara, Y.; Karjalainen, M.; Kerszberg, D.; Kobayashi, Y.; Kubo, H.; Kushida, J.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Machado de Oliveira Fraga, B.; Maggio, C.; Majumdar, P.; Makariev, M.; Mallamaci, M.; Maneva, G.; Manganaro, M.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, S.; Miceli, D.; Miener, T.; Minev, M.; Miranda, J. M.; Mirzoyan, R.; Molina, E.; Moralejo, A.; Morcuende, D.; Moreno, V.; Moretti, E.; Neustroev, V.; Nigro, C.; Nilsson, K.; Nishijima, K.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Peñil, P.; Perennes, C.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Priyadarshi, C.; Puljak, I.; Ribó, M.; Rico, J.; Righi, C.; Rugliancich, A.; Saha, L.; Sahakyan, N.; Saito, T.; Sakurai, S.; Satalecka, K.; Saturni, F. G.; Schmidt, K.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Spolon, A.; Stamerra, A.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Takahashi, M.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vanzo, G.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Will, M.; Wunderlich, C.; Zarić, D.; Baack, D.; Balbo, M.; Biederbeck, N.; Biland, A.; Bretz, T.; Buss, J.; Dorner, D.; Eisenberger, L.; Elsaesser, D.; Hildebrand, D.; Iotov, R.; Mannheim, K.; Neise, D.; Noethe, M.; Paravac, A.; Rhode, W.; Schleicher, B.; Sliusar, V.; Walter, R.; D'Ammando, F.; Horan, D.; Lien, A. Y.; Baloković, M.; Madejski, G. M.; Perri, M.; Verrecchia, F.; Leto, C.; Lähteenmäki, A.; Tornikoski, M.; Ramakrishnan, V.; Järvelä, E.; Vera, R. J. C.; Chamani, W.; Villata, M.; Raiteri, C. M.; Gupta, A. C.; Pandey, A.; Fuentes, A.; Agudo, I.; Casadio, C.; Semkov, E.; Ibryamov, S.; Marchini, A.; Bachev, R.; Strigachev, A.; Ovcharov, E.; Bozhilov, V.; Valcheva, A.; Zaharieva, E.; Damljanovic, G.; Vince, O.; Larionov, V. M.; Borman, G. A.; Grishina, T. S.; Hagen-Thorn, V. A.; Kopatskaya, E. N.; Larionova, E. G.; Larionova, L. V.; Morozova, D. A.; Nikiforova, A. A.; Savchenko, S. S.; Troitskiy, I. S.; Troitskaya, Y. V.; Vasilyev, A. A.; Merkulova, O. A.; Chen, W. P; Samal, M.; Lin, H. C.; Moody, J. W.; Sadun, A. C.; Jorstad, S. G.; Marscher, A. P.; Weaver, Z. R.; Feige, M.; Kania, J.; Kopp, M.; Kunkel, L.; Reinhart, D.; Scherbantin, A.; Schneider, L.; Lorey, C.; Acosta-Pulido, J. A.; Carnerero, M. I.; Carosati, D.; Kurtanidze, S. O.; Kurtanidze, O. M.; Nikolashvili, M. G.; Chigladze, R. A.; Ivanidze, R. Z.; Kimeridze, G. N.; Sigua, L. A.; Joner, M. D.; Spencer, M.; Giroletti, M.; Marchili, N.; Righini, S.; Rizzi, N.; Bonnoli, G.; MAGIC Collaboration; Fact Collaboration.-- This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Aims. We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with a special focus on the multi-band flux correlations. Methods. The dataset has been collected through an extensive multi-wavelength campaign organised between 2016 December and 2017 June. The instruments involved are MAGIC, FACT, Fermi-LAT, Swift, GASP-WEBT, OVRO, Medicina, and Metsahovi. Additionally, four deep exposures (several hours long) with simultaneous MAGIC and NuSTAR observations allowed a precise measurement of the falling segments of the two spectral components. Results. The very-high-energy (VHE; E 100 GeV) gamma rays and X-rays are positively correlated at zero time lag, but the strength and characteristics of the correlation change substantially across the various energy bands probed. The VHE versus X-ray fluxes follow dierent patterns, partly due to substantial changes in the Compton dominance for a few days without a simultaneous increase in the X-ray flux (i.e., orphan gamma-ray activity). Studying the broadband spectral energy distribution (SED) during the days including NuSTAR observations, we show that these changes can be explained within a one-zone leptonic model with a blob that increases its size over time. The peak frequency of the synchrotron bump varies by two orders of magnitude throughout the campaign. Our multi-band correlation study also hints at an anti-correlation between UV-optical and X-ray at a significance higher than 3. A VHE flare observed on MJD 57788 (2017 February 4) shows gamma-ray variability on multi-hour timescales, with a factor ten increase in the TeV flux but only a moderate increase in the keV flux. The related broadband SED is better described by a two-zone leptonic scenario rather than by a one-zone scenario.We find that the flare can be produced by the appearance of a compact second blob populated by high energetic electrons spanning a narrow range of Lorentz factors, from 0 min = 2104 to 0 max = 6105. © 2021 Georg Thieme Verlag. All rights reserved., The MAGIC Collaboration would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovación (MICINN) (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-5-R, FPA2017-90566-REDC, PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-105510GB-C31,PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, PID2019-107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588, SEV-2017-0709 and CEX2019-000920-S, and “María de Maeztu” CEX2019-000918-M, the Unidad de Excelencia “María de Maeztu” MDM-2015-0509-18-2 and the “la Caixa” Foundation (fellowship LCF/BQ/PI18/11630012) and by the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; the Polish National Research Centre grant UMO-2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq and FAPERJ. The important contributions from ETH Zurich grants ETH-10.08-2 and ETH-27.12-1 as well as the funding by the Swiss SNF and the German BMBF (Verbundforschung Astro- und Astroteilchenphysik) and HAP (Helmoltz Alliance for Astroparticle Physics) are gratefully acknowledged. Part of this work is supported by Deutsche Forschungsgemeinschaft (DFG) within the Collaborative Research Center SFB 876 “Providing Information by Resource-Constrained Analysis”, project C3. We are thankful for the very valuable contributions from E. Lorenz, D. Renker and G. Viertel during the early phase of the project. We thank the Instituto de Astrofísica de Canarias for allowing us to operate the telescope at the Observatorio del Roque de los Muchachos in La Palma, the Max-Planck-Institut für Physik for providing us with the mount of the former HEGRA CT3 telescope, and the MAGIC collaboration for their support. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC; Italy) and the California Institute of Technology (USA). This research has also made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. A.A.E and D.P acknowledge support from the Deutsche Forschungs gemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC-2094 – 390783311. M. B. acknowledges support from the YCAA Prize Postdoctoral Fellowship and from the Black Hole Initiative at Harvard University, which is funded in part by the Gordon and Betty Moore Foundation (grant GBMF8273) and in part by the John Templeton Foundation. This publication makes use of data obtained at the Metsähovi Radio Observatory, operated by Aalto University in Finland. This research has made use of data from the OVRO 40-m monitoring program (Richards et al. 2011) which is supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G and NSF grants AST-0808050 and AST-1109911. I.A. acknowledges financial support from the Spanish “Ministerio de Ciencia e Innovación” (MCINN) through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía-CSIC (SEV-2017-0709). Acquisition and reduction of the MAPCAT data was supported in part by MICINN through grants AYA2016-80889-P and PID2019-107847RB-C44. The MAPCAT observations were carried out at the German-Spanish Calar Alto Observatory, which is jointly operated by Junta de Andalucía and Consejo Superior de Investigaciones Científicas. C.C. acknowledges support from the European Research Council (ERC) under the European Union Horizon 2020 research and innovation program under the grant agreement No 771282. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants KP-06-H28/3 (2018), KP-06-H38/4 (2019) and KP-06-KITAJ/2 (2020). We acknowledge support by Bulgarian National Science Fund under grant DN18-10/2017 and National RI Roadmap Projects DO1-277/16.12.2019 and DO1-268/16.12.2019 of the Ministry of Education and Science of the Republic of Bulgaria. This research was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract No 451-03-68/2020-14/200002). G.D. acknowledges 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” (2020–2022, head – G. Damljanovic). The BU group was supported in part by NASA Fermi guest investigator program grants 80NSSC19K1505 and 80NSSC20K1566. This study was based in part on observations conducted using the 1.8 m Perkins Telescope Observatory (PTO) in Arizona, which is owned and operated by Boston University. This article is partly based 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 article is also based partly on data obtained with the STELLA robotic telescopes in Tenerife, an AIP facility jointly operated by AIP and IAC. The Abastumani team acknowledges financial support by the Shota Rustaveli National Science Foundation under contract FR-19-6174. Based on observations with the Medicina telescope operated by INAF – Istituto di Radioastronomia.
Published: 2021
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16. Polarimetric Properties of Blazars Caught by the WEBT

Author: C. M. Raiteri, M. Villata, and ITA
Subjects: jets, Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, blazars, Polarimetry, FOS: Physical sciences, Context (language use), QB1-991, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, Telescope, Astrophysical jet, law, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, polarimetry, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, Line-of-sight, 010308 nuclear & particles physics, Astronomy and Astrophysics, active galactic nuclei, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Active galactic nuclei come in many varieties. A minority of them are radio-loud, and exhibit two opposite prominent plasma jets extending from the proximity of the supermassive black hole up to megaparsec distances. When one of the relativistic jets is oriented closely to the line of sight, its emission is Doppler beamed and these objects show extreme variability properties at all wavelengths. These are called "blazars". The unpredictable blazar variability, occurring on a continuous range of time-scales, from minutes to years, is most effectively investigated in a multi-wavelength context. Ground-based and space observations together contribute to give us a comprehensive picture of the blazar emission properties from the radio to the gamma-ray band. Moreover, in recent years, a lot of effort has been devoted to the observation and analysis of the blazar polarimetric radio and optical behaviour, showing strong variability of both the polarisation degree and angle. The Whole Earth Blazar Telescope (WEBT) Collaboration, involving many tens of astronomers all around the globe, has been monitoring several blazars since 1997. The results of the corresponding data analysis have contributed to the understanding of the blazar phenomenon, particularly stressing the viability of a geometrical interpretation of the blazar variability. We review here the most significant polarimetric results achieved in the WEBT studies., Comment: Review published in "Galaxies" as part of the Special Issue "Polarimetry as a Probe of Magnetic Fields in AGN Jets", Academic Editors: Margo Aller, Jose L. G\'omez and Eric Perlman
Published: 2021

17. Studying the Extreme Behaviour of 1ES 2344+51.4

Author: Daniela Dorner, Alexei V. Filippenko, Valeri M. Larionov, Vandad Fallah Ramazani, Vitalii Sliusar, Marina Manganaro, J. A. Acosta-Pulido, C. M. Raiteri, WeiKang Zheng, Axel Arbet-Engels, Matteo Cerruti, and Talvikki Hovatta
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, Redshift, Spectral line, Synchrotron, law.invention, Crab Nebula, 13. Climate action, law, Spectral energy distribution, MAGIC (telescope), Astrophysics - High Energy Astrophysical Phenomena, Flare
Abstract: The BL Lac type object 1ES 2344+51.4 (redshift z = 0.044) was one of the first sources to be included in the extreme high-peaked BL Lac (EHBL) family. EHBLs are characterised by a broadband spectral energy distribution (SED) featuring the synchrotron peak above ∼ 1017 Hz. From previous studies of 1ES 2344+51.4 in the very-high-energy (VHE, >100 GeV) gamma-ray range, its inverse Compton (IC) peak is expected around 200 GeV. 1ES 2344+51.4 was first detected in the VHE range by Whipple in 1995 during a very bright outburst showing around 60% of the flux of the Crab Nebula above 350 GeV. In 1996, during another flare in the X-ray band, observations with Beppo-SAX revealed a large 0.1-10 keV flux variability on timescales of a few hours and an impressive frequency shift of the synchrotron peak to above 1018 Hz. Later on, this extreme behaviour of the source motivated several multiwavelength campaigns, during most of which the source appeared to be in a low state and showing no clear signs of “extremeness”. In August 2016, FACT detected 1ES 2344+51.4 in a high state and triggered multiwavelength observations. The VHE observations show a flux level similar to the historical maximum of 1995. The combination of MAGIC, FACT, and Fermi-LAT spectra provides an unprecedented characterisation of the IC peak. It is the first time that simultaneous HE and VHE data are presented for this object during a flaring episode. We find an atypically hard spectrum in the VHE γ-rays as well as a hard X-ray spectrum, revealing a renewed extreme behaviour., PoS: Proceedings of Science, 358, ISSN:1824-8039, Proceedings of 36th International Cosmic Ray Conference (ICRC 2019)
Published: 2021
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18. The Galactic Anticentre

Author: Vincenzo Ripepi, A. de Torres, Annie C. Robin, Mariateresa Crosta, C. Diener, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, K. Kruszyńska, E. Fraile, André Moitinho, Michał Pawlak, P. Panuzzo, M. Riello, Benoit Carry, A. Yoldas, Harry Enke, N. Tonello, P. Gavras, M. Vaillant, Rosanna Sordo, E. del Pozo, Lorenzo Rimoldini, M. Bernet, G. Orrù, W. van Reeven, J. M. Martín-Fleitas, S. Diakite, P. Burgess, P. Osborne, Derek W. Morris, M. I. Carnerero, Amina Helmi, Mike Smith, Iain A. Steele, Alessandro Sozzetti, M. Kontizas, A. Sagristà Sellés, Roberto Molinaro, B. Holl, D. Baines, D. Molina, J. Fernández-Hernández, S. Marinoni, Michele Bellazzini, Maria Süveges, Teresa Antoja, D. Barbato, Uwe Lammers, Isabella Pagano, Davide Massari, G. Plum, P. Ramos, G. Jevardat de Fombelle, M. Biermann, C. Crowley, Mathias Schultheis, D. W. Evans, P. A. Palicio, Paolo Montegriffo, Ramachrisna Teixeira, R. Blomme, Elmé Breedt, T. A. Lister, F. A. Jansen, Ruth Carballo, Marcella Marconi, A. Abreu Aramburu, J. M. Carrasco, F. Royer, S. Accart, A. Burlacu, S. Regibo, Andrej Prsa, M. Sarasso, Nicolas Rambaux, A. F. Mulone, Ana Ulla, Eric Gosset, Alessandra Mastrobuono-Battisti, George M. Seabroke, H. E. Delgado, Federico Marocco, C. Nicolas, T. Lebzelter, Nami Mowlavi, C. Barache, Nicoletta Sanna, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Silvio Leccia, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, F. Figueras, G. Busso, C. Fabre, P. Di Matteo, F. Riclet, F. Solitro, Eric Slezak, N. Samaras, João Alves, Emese Plachy, Timo Prusti, F. van Leeuwen, J. Osinde, O. Marchal, M. Ajaj, C. Ducourant, Tatiana Muraveva, Shay Zucker, H. Steidelmüller, Alberto Riva, D. Semeux, N. Cheek, Laurent Galluccio, Martin A. Barstow, Alex Bombrun, S. Liao, M. van Leeuwen, R. E. de Souza, P. de Laverny, T. Roegiers, Paul J. McMillan, G. Holland, Alexey Mints, G. Giuffrida, L. M. Sarro, Juan Zorec, G. Sadowski, P. Yvard, Carme Jordi, J. L. Halbwachs, Laurent Chemin, Ludovic Delchambre, M. Garcia-Reinaldos, Ugo Becciani, Diego Bossini, Ángel Gómez, Sergi Blanco-Cuaresma, Rossella Cancelliere, C. Fabricius, J. De Ridder, L. Eyer, L. Pulone, Simon Hodgkin, Ennio Poretti, F. De Angeli, M. Haywood, E. Anglada Varela, Antonella Vallenari, F. X. Pineau, D. Garabato, A. Guerrier, H. E. P. Lindstrøm, Thomas Hilger, I. Bellas-Velidis, Frédéric Arenou, Paolo Giacobbe, Ilaria Musella, Tristan Cantat-Gaudin, L. Palaversa, Pedro García-Lario, David Hobbs, C. Turon, E. Balbinot, P. de Teodoro, Sébastien Lambert, D. Katz, Angela Bragaglia, Anthony G. A. Brown, Paolo Tanga, P. Castro Sampol, J. C. Segovia, Alejandra Recio-Blanco, Yves Fremat, Jon Marchant, Jose M Hernandez, S. Ragaini, Sofia Randich, P. Re Fiorentin, J. F. Le Campion, Gisella Clementini, M. Segol, P. David, R. Drimmel, F. Crifo, J. Guiraud, M. David, R. L. Smart, M. Fabrizio, I. Gonzalez-Santamaria, D. Eappachen, M. G. Lattanzi, Miguel García-Torres, Andreas Korn, S. Voutsinas, László Molnár, Simchon Faigler, A. Mora, Nicholas Rowell, Antti Penttilä, R. Geyer, Sanjeev Khanna, Aldo Dell'Oro, H. E. Huckle, C. Dolding, N. Leclerc, Monica Rainer, R. Mor, J. Bakker, Maroussia Roelens, Douglas J. Marshall, A. G. Butkevich, Nigel Hambly, A. Masip, Laia Casamiquela, R. Messineo, Martin Altmann, A. M. Piersimoni, Alessandro Spagna, Gerry Gilmore, Stefano Bertone, Patrick Charlot, O. Vanel, Daniel Hestroffer, Marco Castellani, Sebastian L. Hidalgo, W. Roux, Łukasz Wyrzykowski, Krzysztof A. Rybicki, M. M. S. Marcos Santos, Raphael Guerra, Alberto Cellino, E. Poggio, Gérard Jasniewicz, J. J. González-Vidal, S. Cowell, Peter G. Jonker, C. M. Raiteri, S. Bartolomé, J. Álvarez Cid-Fuentes, Elisabetta Caffau, J. J. Aguado, N. R. Millar, Ulrike Heiter, Federica Spoto, Felix Franke, A. Baudesson-Stella, M. Barros, Tsevi Mazeh, A. Panahi, E. Brugaletta, R. Buzzi, Elena Pancino, G. Altavilla, E. Racero, Enrique Solano, Mikael Granvik, Minia Manteiga, C. Robin, Tomaz Zwitter, Deborah Busonero, Alberto Krone-Martins, Marc Audard, Kevin Benson, Christos Siopis, L. Balaguer-Núñez, C. A. L. Bailer-Jones, E. Poujoulet, O. L. Creevey, E. Szegedi-Elek, C. Fouron, Michael Davidson, E. Licata, Despina Hatzidimitriou, Mark Cropper, Z. Kostrzewa-Rutkowska, S. Managau, A. Dapergolas, Sergio Messina, Laszlo Szabados, H. I. Siddiqui, W. Löffler, Mario Gai, J.-B. Delisle, Leanne P. Guy, S. G. Baker, W. J. Cooper, Alfred Castro-Ginard, Conny Aerts, A. Lorca, Xavier Luri, Damien Ségransan, Grigori Fedorets, A. Garofalo, J. Juaristi Campillo, F. De Luise, F. Pailler, F. Taris, L. Bramante, Thierry Morel, T. Cornez, L. Martin Polo, M. Ramos-Lerate, Jordi Portell, E. Salguero, Sergei A. Klioner, K. Janßen, Ulrich Bastian, Stefan Jordan, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Y. Lebreton, Carlos Dafonte, S. Girona, D. Munoz, Dimitri Pourbaix, William Thuillot, J. H. J. de Bruijne, N. Brouillet, L. Chaoul, F. Torra, Alex Lobel, J.-L. Bassilana, Francesca Fragkoudi, M. Romero-Gómez, C. A. Stephenson, T. Pauwels, Eva Sciacca, Alessandro Bressan, Morgan Fouesneau, E. Livanou, E. Gerlach, X. Peñalosa Esteller, Roberto Morbidelli, L. Rohrbasser, Johannes Sahlmann, Elisa Distefano, P. Sartoretti, Karri Muinonen, Zoltan Balog, Y. Viala, J. Torra, H. Zhao, L. Siltala, G. Tauran, D. Souami, P. Madrero Pardo, David Teyssier, Jesus Salgado, J. Souchay, C. P. Murphy, Maria-Rosa L. Cioni, N. A. Walton, S. Bouquillon, Andrea Chiavassa, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Yassine Damerdji, Richard I. Anderson, Pierre Fernique, Céline Reylé, M. Hauser, E. Utrilla, Pierre Kervella, C. Zurbach, Robert G. Mann, Ummi Abbas, Hector Canovas, D. L. Harrison, Y. Lasne, Mark Taylor, Y. Le Fustec, E. F. del Peloso, N. Bauchet, E. van Dillen, Jan Rybizki, N. Hładczuk, T. Boch, J. González-Núñez, Carine Babusiaux, C. Pagani, Krzysztof Nienartowicz, Eduard Masana, G. Kordopatis, N. Robichon, Luciana Bianchi, R. Gutiérrez-Sánchez, Arnaud Siebert, A. Kochoska, T. Carlucci, Jérôme Berthier, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, European Commission, Centros de Excelencia Severo Ochoa, BARCELONA SUPERCOMPUTING CENTER (BSC), SEV2015-0493, Krone Martins, A. [0000-0002-2308-6623], McMillan, P. [0000-0002-8861-2620], Carrasco Martínez, J. P. [0000-0002-3029-5853], Sozzetti, A. [0000-0002-7504-365X], Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MINECO/ICTI2013-2016/MDM-2014-0369, Centrode Excelencia Científica Instituto de Ciencias del Cosmos Universidad de Barcelona, MINECO/ICTI2013-2016/SEV2015-0493, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), National Natural Science Foundation of China (NSFC), Estonian Ministry of Education and Research, Centre National D'Etudes Spatiales (CNES), Agence Nationale de la Recherche (ANR), Centre National de la Recherche Scientifique (CNRS), European Commission (EC), European Research Council (ERC), Institut des Sciences de l'Univers (INSU), Institut National Polytechnique (INP), Institut National de Physique nucleaire et de Physique des Particules (IN2P3), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Hungarian Academy of Sciences, Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Italian Istituto Nazionale di Astrofisica (INAF), Netherlands Organisation for Scientific Research (NWO), Polish National Science Centre, Ministry of Science and Higher Education (MNiSW), Fundacao para a Ciencia e a Tecnologia (FCT), Slovenian Research Agency, Agencia Estatal de Investigación (AEI), Generalitat de Catalunya, United Kingdom Science and Technology Facilities Council (STFC), United Kingdom Space Agency (UKSA), Gaia Collaboration, Universidad de Cantabria, Astronomy, Kapteyn Astronomical Institute, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), M2A 2021, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: trigonometric parallaxes, SOLAR NEIGHBORHOOD, Astronomy, SAGITTARIUS DWARF GALAXY, Astrophysics, 01 natural sciences, sagittarius dwarf galaxy, 010303 astronomy & astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], solar neighborhood, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, Gelexy: kinematics and dynamics, Kinematics and Dynamics, Open clusters and asssociations: individual: Berkeley 29, sky survey, Disk, Physical Sciences, kinematics and dynamics [Gelexy], old open clusters, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, open clusters and associations: individual: Berkeley 29, Galaxy: kinematics and dynamics, disk [Galaxy], individual: Berkeley 29 [open clusters and associations], Astrometria, Berkeley 29, EXPLORING HALO SUBSTRUCTURE, LOCAL KINEMATICS, Milky Way, FOS: Physical sciences, Open Clusters and Associations, Individual, exploring halo substructure, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Computer Science::Digital Libraries, stellar structure, Galaxy: disk, Open clusters and associations: individual: Saurer 1, Galactic halo, Halo, Settore FIS/05 - Astronomia e Astrofisica, individual: Berkeley 29 [Open clusters and asssociations], 0103 physical sciences, distances [stars], halo [Galaxy], Disc, Stars: distances, milky-way, Saurer 1, Astrophysics::Galaxy Astrophysics, canis-major, Science & Technology, 010308 nuclear & particles physics, TRIGONOMETRIC PARALLAXES, Galaxy: halo, stars: distances, open clusters and associations: individual: Saurer 1, Astrophysics - Astrophysics of Galaxies, Astronomy and Astrophysics, Galactic plane, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, CANIS-MAJOR, Stars, Galaxy, Physics::History of Physics, Estels, individual: Saurer 1 [open clusters and associations], Distances, local kinematics, OLD OPEN CLUSTERS, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SKY SURVEY, Open cluster, STELLAR STRUCTURE
Abstract: Aims. We aim to demonstrate the scientific potential of the Gaia Early Data Release 3 (EDR3) for the study of different aspects of the Milky Way structure and evolution and we provide, at the same time, a description of several practical aspects of the data and examples of their usage., Methods. We used astrometric positions, proper motions, parallaxes, and photometry from EDR3 to select different populations and components and to calculate the distances and velocities in the direction of the anticentre. In this direction, the Gaia astrometric data alone enable the calculation of the vertical and azimuthal velocities; also, the extinction is relatively low compared to other directions in the Galactic plane. We then explore the disturbances of the current disc, the spatial and kinematical distributions of early accreted versus in situ stars, the structures in the outer parts of the disc, and the orbits of open clusters Berkeley 29 and Saurer 1., Results. With the improved astrometry and photometry of EDR3, we find that: (i) the dynamics of the Galactic disc are very complex with oscillations in the median rotation and vertical velocities as a function of radius, vertical asymmetries, and new correlations, including a bimodality with disc stars with large angular momentum moving vertically upwards from below the plane, and disc stars with slightly lower angular momentum moving preferentially downwards; (ii) we resolve the kinematic substructure (diagonal ridges) in the outer parts of the disc for the first time; (iii) the red sequence that has been associated with the proto-Galactic disc that was present at the time of the merger with Gaia-Enceladus-Sausage is currently radially concentrated up to around 14 kpc, while the blue sequence that has been associated with debris of the satellite extends beyond that; (iv) there are density structures in the outer disc, both above and below the plane, most probably related to Monoceros, the Anticentre Stream, and TriAnd, for which the Gaia data allow an exhaustive selection of candidate member stars and dynamical study; and (v) the open clusters Berkeley 29 and Saurer 1, despite being located at large distances from the Galactic centre, are on nearly circular disc-like orbits., Conclusions. Even with our simple preliminary exploration of the Gaia EDR3, we demonstrate how, once again, these data from the European Space Agency are crucial for our understanding of the different pieces of our Galaxy and their connection to its global structure and history.
Published: 2021
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19. Gaia early data release 3: summary of the contents and survey properties (Corrigendum)

Author: Mathias Schultheis, Marcella Marconi, N. Robichon, Luciana Bianchi, F. Crifo, J. Guiraud, D. Eappachen, R. Gutiérrez-Sánchez, Sanjeev Khanna, A. M. Piersimoni, Raphael Guerra, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, Ummi Abbas, Francesca Figueras, R. Blomme, Elmé Breedt, G. Busso, A. Jean-Antoine Piccolo, Gerry Gilmore, A. Panahi, S. Messina, C. Babusiaux, Łukasz Wyrzykowski, Mark Taylor, Alex Bombrun, M. Barros, M. Riello, M. Ajaj, C. Ducourant, Tatiana Muraveva, Alberto Cellino, E. Poggio, Y. Le Fustec, C. P. Murphy, Maria-Rosa L. Cioni, Hector Canovas, D. L. Harrison, Y. Lasne, Elena Pancino, N. Bauchet, G. Orrù, Sergi Blanco-Cuaresma, Simon Hodgkin, Ennio Poretti, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Andrea Chiavassa, E. Szegedi-Elek, A. G. A. Brown, Laszlo Szabados, A. Masip, Laia Casamiquela, R. Messineo, C. Crowley, Alessandra Mastrobuono-Battisti, E. Poujoulet, Zoltan Balog, L. Eyer, A. Guerrier, H. E. P. Lindstrøm, Ilaria Musella, Laurent Galluccio, Martin A. Barstow, Aldo Dell'Oro, Mark Cropper, Z. Kostrzewa-Rutkowska, Angela Bragaglia, Arnaud Siebert, Damien Ségransan, A. Kochoska, J. L. Halbwachs, E. F. del Peloso, N. Hładczuk, F. Pailler, Stefan Jordan, Stefano Bertone, L. Pulone, Frédéric Arenou, Patrick Charlot, David Hobbs, P. Castro Sampol, Yves Fremat, Sofia Randich, Marc Audard, Despina Hatzidimitriou, A. Dapergolas, L. Palaversa, W. van Reeven, M. Hauser, E. Utrilla, Georges Kordopatis, Sergei A. Klioner, Alex Lobel, J.-L. Bassilana, G. Tauran, T. Prusti, H. Steidelmüller, Alberto Riva, Diego Bossini, Maria Süveges, Isabella Pagano, J. H. J. de Bruijne, Elisabetta Caffau, Federica Spoto, Felix Franke, T. Boch, M. I. Carnerero, T. Carlucci, Grigori Fedorets, J. Castañeda, W. Löffler, Enrique Solano, Paolo Montegriffo, A. Abreu Aramburu, T. Lebzelter, Nami Mowlavi, C. Barache, C. A. Stephenson, A. Lorca, L. Bramante, Amina Helmi, J.-B. Delisle, B. Holl, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, F. van Leeuwen, C. Robin, D. Katz, E. Gerlach, Elisa Distefano, Michele Bellazzini, P. de Laverny, G. Sadowski, Tomaz Zwitter, A. Burlacu, Teresa Antoja, Rossella Cancelliere, F. Torra, C. Pagani, Annie C. Robin, Johannes Sahlmann, Karri Muinonen, Eva Sciacca, D. Vicente, Krzysztof Nienartowicz, A. F. Mulone, Shay Zucker, Nicholas Rowell, H. E. Delgado, Dimitri Pourbaix, G. Giuffrida, H. E. Huckle, Federico Marocco, L. Noval, Daniel Michalik, P. J. Richards, Y. Viala, E. van Dillen, L. Karbevska, H. Zhao, L. Siltala, Nicoletta Sanna, K. Kruszyńska, E. Fraile, R. De March, Y. Lebreton, C. M. Raiteri, D. W. Evans, Ana Ulla, Francesca Fragkoudi, Jan Rybizki, E. Brugaletta, L. Rohrbasser, Andreas Korn, S. G. Baker, A. Garcia-Gutierrez, L. M. Sarro, R. Buzzi, T. Pauwels, Jérôme Berthier, L. Chaoul, W. J. Cooper, Eduard Masana, M. van Leeuwen, D. Garabato, P. Panuzzo, Maroussia Roelens, Benoit Carry, Deborah Busonero, Michael Davidson, J. González-Núñez, Thomas Hilger, E. Licata, M. Weiler, Mikael Granvik, Alessandro Bressan, Morgan Fouesneau, Miguel García-Torres, W. Roux, Pedro García-Lario, Iain A. Steele, P. Ramos, Alessandro Sozzetti, Roberto Molinaro, O. L. Creevey, D. Barbato, Lorenzo Rimoldini, Uwe Lammers, Alexey Mints, P. Sartoretti, E. Livanou, D. Souami, P. Madrero Pardo, David Teyssier, M. Bernet, Yassine Damerdji, X. Peñalosa Esteller, C. Fabre, F. Thévenin, Gérard Jasniewicz, Roberto Morbidelli, Jesus Salgado, Juan Zorec, Ángel Gómez, Douglas J. Marshall, A. G. Butkevich, M. Biermann, E. Racero, J. Torra, R. Gomel, O. Vanel, Daniel Hestroffer, Sebastian L. Hidalgo, P. A. Palicio, F. De Angeli, Richard L. Smart, J. M. Martín-Fleitas, Derek W. Morris, F. Royer, S. Diakite, S. Accart, C. Dolding, P. Burgess, Richard I. Anderson, A. Garofalo, I. Bellas-Velidis, George M. Seabroke, P. Osborne, Claus Fabricius, Jon Marchant, Ramachrisna Teixeira, João Alves, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Paolo Giacobbe, Emese Plachy, M. Fabrizio, I. Gonzalez-Santamaria, F. Taris, Kevin Benson, Christos Siopis, M. M. S. Marcos Santos, S. Cowell, Jose M Hernandez, S. Ragaini, Jordi Portell, Linda K. Molnar, R. Drimmel, Pierre Kervella, C. Zurbach, S. Bartolomé, J. Álvarez Cid-Fuentes, E. Salguero, Ulrich Bastian, Robert G. Mann, Marco Castellani, J. Osinde, E. Balbinot, Caroline Soubiran, Rene Andrae, J. Souchay, M. G. Lattanzi, S. Voutsinas, Agnes Fienga, Giovanni Comoretto, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Carlos Dafonte, Alfred Castro-Ginard, J. C. Segovia, Monica Rainer, F. Julbe, A. Hutton, Peter G. Jonker, William Thuillot, A. de Torres, F. De Luise, Pierre Fernique, Céline Reylé, M. Kontizas, G. Plum, Martin Altmann, L. Martin Polo, M. Ramos-Lerate, P. de Teodoro, Sébastien Lambert, G. Altavilla, André Moitinho, D. Munoz, N. Brouillet, Alessandro Spagna, C. Ordénovic, Gisella Clementini, C. Nicolas, Michał Pawlak, Silvio Leccia, A. Delgado, M. Romero-Gómez, N. Cheek, A. Yoldas, Harry Enke, Rosanna Sordo, V. Sanchez Gimenez, Mike Smith, P. David, D. Baines, Paolo Tanga, Guy Rixon, Alberto Krone-Martins, S. Managau, N. A. Walton, S. Bouquillon, C. Fouron, Francois Mignard, Xavier Luri, J. Juaristi Campillo, S. Girona, Thierry Morel, T. Cornez, P. M. Marrese, M. A. Álvarez, S. Liao, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, E. Anglada Varela, Antonella Vallenari, S. Regibo, R. E. de Souza, Sahar Shahaf, J. De Ridder, M. Segol, Simchon Faigler, A. Mora, Ulrike Heiter, Carla Cacciari, Minia Manteiga, H. I. Siddiqui, Mario Gai, Leanne P. Guy, N. Leclerc, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Bengt Edvardsson, P. Di Matteo, K. Janßen, F. Riclet, F. Solitro, O. Marchal, G. Holland, F. X. Pineau, C. Turon, P. Re Fiorentin, Tsevi Mazeh, Mariateresa Crosta, C. Diener, J. F. Le Campion, Vincenzo Ripepi, M. David, R. Mor, N. Tonello, E. del Pozo, J. Bakker, Davide Massari, A. Sagristà Sellés, Marco Delbo, Eric Slezak, P. Gavras, N. Samaras, S. Marinoni, M. Vaillant, J. M. Petit, P. Yvard, Carme Jordi, Ugo Becciani, Antti Penttilä, R. Geyer, Nigel Hambly, Krzysztof A. Rybicki, L. Balaguer-Núñez, C. A. L. Bailer-Jones, Conny Aerts, Eric Gosset, D. Semeux, T. Roegiers, and Laurent Chemin
Subjects: Physics, Addenda, 010504 meteorology & atmospheric sciences, Errata, Parallaxes, Astronomy, Astronomy and Astrophysics, Astrophysics, Astrometry, Photometric, 01 natural sciences, Techniques, catalogs, astrometry, parallaxes, proper motions, techniques: photometric, errata, addenda, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, 0103 physical sciences, Proper motions, Catalogs, 010303 astronomy & astrophysics, Data release, 0105 earth and related environmental sciences
Abstract: We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G_BP-G_RP) colour are also available. The passbands for G, G_BP, and G_RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 percent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30--40 percent for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G_BP, and G_RP is valid over the entire magnitude and colour range, with no systematics above the 1 percent level.
Published: 2021

20. The complex variability of blazars: time-scales and periodicity analysis in S4 0954+65

Author: A. A. Nikiforova, Efthalia Traianou, Sergey S. Savchenko, J. Escudero, L. V. Larionova, T. S. Andreeva, V. Bozhilov, W. J. Hou, An-Li Tsai, Carolina Casadio, Anne Lähteenmäki, Ioannis Myserlis, Merja Tornikoski, A. Fuentes, J. A. Acosta-Pulido, I. Agudo, S. O. Kurtanidze, A. A. Arkharov, F. D'Ammando, M. I. Carnerero, M. Hart, D. Ivanov, Goran Damljanović, Evgeni Semkov, M. Stojanovic, J. Otero-Santos, Y. V. Troitskaya, I. Rahimov, Wen Ping Chen, E. N. Kopatskaya, D. Shakhovskoy, Alok C. Gupta, Rumen Bachev, D. Carosati, A. Strigachev, Antoniya Valcheva, Elena G. Larionova, M. Nakamura, M. G. Nikolashvili, Alan P. Marscher, G. A. Borman, Valeri M. Larionov, N. Marchili, Z. R. Weaver, T. Pursimo, Marcello Giroletti, Marco Berton, C. Konstantopoulou, Simona Righini, O. M. Kurtanidze, I. Björklund, T. Sakamoto, C. M. Raiteri, M. Villata, T. S. Grishina, Evgeni Ovcharov, M. Minev, J. Y. Kim, E. Zaharieva, Vladimir A. Hagen-Thorn, S. G. Jorstad, Clemens Thum, D. A. Morozova, O. Vince, A. A. Vasilyev, G. Markovic, Givi N. Kimeridze, Lorand A. Sigua, Erika Benítez, David Hiriart, I. S. Troitskiy, National Aeronautics and Space Administration (US), Ministry of Education, Science and Technological Development (Serbia), Bulgarian National Science Fund, Shota Rustaveli National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), National Institute for Astrophysics, St. Petersburg State University, Boston University, Instituto de Astrofísica de Canarias, CSIC, Russian Academy of Sciences, RAS - Pulkovo Astronomical Observatory, Bulgarian Academy of Sciences, Universidad Nacional Autónoma de México, Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Sofia University St. Kliment Ohridski, EPT Observatories, Institute of Electronic Structure and Laser, National Central University, University of Belgrade, Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, Aryabhatta Research Institute of Observational Sciences, Korea Astronomy and Space Science Institute, Georgian National Academy of Sciences, Nordic Optical Telescope, Max Planck Institute for Radio Astronomy, Aoyama Gakuin University, IRAM, Aalto-yliopisto, and Aalto University
Subjects: individual: S4 0954+65 [BL Lacertae objects], active [Galaxies], BL Lacertae objects: individual: S4 0954+65, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Library science, 7. Clean energy, 01 natural sciences, IRAM 30m telescope, Observatory, 0103 physical sciences, Bulgarian, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, general [BL Lacertae objects], 010308 nuclear & particles physics, Astronomy and Astrophysics, Galaxies: active, BL Lacertae objects: general, Astrophysics - Astrophysics of Galaxies, language.human_language, Joint research, Galaxies: jets, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), language, jets [Galaxies], Christian ministry, Astrophysics - High Energy Astrophysical Phenomena, Administration (government)
Abstract: Full list of authors: Raiteri, C. M.; Villata, M.; Larionov, V. M.; Jorstad, S. G.; Marscher, A. P.; Weaver, Z. R.; Acosta-Pulido, J. A.; Agudo, I.; Andreeva, T.; Arkharov, A.; Bachev, R.; Benítez, E.; Berton, M.; Björklund, I.; Borman, G. A.; Bozhilov, V.; Carnerero, M. I.; Carosati, D.; Casadio, C.; Chen, W. P. Damljanovic, G.; D'Ammando, F.; Escudero, J.; Fuentes, A.; Giroletti, M.; Grishina, T. S.; Gupta, A. C.; Hagen-Thorn, V. A.; Hart, M.; Hiriart, D.; Hou, W. -J.; Ivanov, D.; Kim, J. -Y.; Kimeridze, G. N.; Konstantopoulou, C.; Kopatskaya, E. N.; Kurtanidze, O. M.; Kurtanidze, S. O.; Lähteenmäki, A.; Larionova, E. G.; Larionova, L. V.; Marchili, N.; Markovic, G.; Minev, M.; Morozova, D. A.; Myserlis, I.; Nakamura, M.; Nikiforova, A. A.; Nikolashvili, M. G.; Otero-Santos, J.; Ovcharov, E.; Pursimo, T.; Rahimov, I.; Righini, S.; Sakamoto, T.; Savchenko, S. S.; Semkov, E. H.; Shakhovskoy, D.; Sigua, L. A.; Stojanovic, M.; Strigachev, A.; Thum, C.; Tornikoski, M.; Traianou, E.; Troitskaya, Y. V.; Troitskiy, I. S.; Tsai, A.; Valcheva, A.; Vasilyev, A. A.; Vince, O.; Zaharieva, E., Among active galactic nuclei, blazars show extreme variability properties. We here investigate the case of the BL Lac object S4 0954+65 with data acquired in 2019-2020 by the Transiting Exoplanet Survey Satellite (TESS) and by the Whole Earth Blazar Telescope (WEBT) Collaboration. The 2-min cadence optical light curves provided by TESS during three observing sectors of nearly 1 month each allow us to study the fast variability in great detail. We identify several characteristic short-term time-scales, ranging from a few hours to a few days. However, these are not persistent, as they differ in the various TESS sectors. The long-term photometric and polarimetric optical and radio monitoring undertaken by the WEBT brings significant additional information, revealing that (i) in the optical, long-term flux changes are almost achromatic, while the short-term ones are strongly chromatic; (ii) the radio flux variations at 37 GHz follow those in the optical with a delay of about 3 weeks; (iii) the range of variation of the polarization degree and angle is much larger in the optical than in the radio band, but the mean polarization angles are similar; (iv) the optical long-term variability is characterized by a quasi-periodicity of about 1 month. We explain the source behaviour in terms of a rotating inhomogeneous helical jet, whose pitch angle can change in time. © 2021 The Author(s)., This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. 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. This article is partly based on observations made in the Observatorios de Canarias del IAC with the Liverpool telescope operated on the island of La Palma by the Liverpool John Moores University in the Observatorio del Roque de Los Muchachos. This article is partly based 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 article 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. Many thanks are due to the IAC support astronomers and telescope operators for supporting the observations at the IAC-80 telescope. This publication makes use of data obtained at Metsähovi Radio Observatory, operated by Aalto University in Finland. This research has made use of NASA’s Astrophysics Data System and of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The research at Boston University was supported by NASA grants 80NSSC20K1566 (Fermi Guest Investigator Program) and 80NSSC21K0243 (TESS Guest Investigator Program). 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. GD, MS, GM, and OV acknowledge the 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’ (2020–2022, leader is G.Damljanovic), and support by the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract No 451-03-68/2020-14/200002) This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants DN 18-13/2017, KP-06-H28/3 (2018), KP-06-H38/4 (2019), and KP-06-KITAJ/2 (2020). SOK acknowledges financial support by Shota Rustaveli National Science Foundation of Georgia under contract PHDF-18-354 EB acknowledges support from DGAPA-PAPIIT GRANT IN113320. This work is partly based upon observations carried out at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir (OAN- SPM), Baja California, Mexico. We acknowledge support by Bulgarian National Science Fund under grant DN18-10/2017 and National RI Roadmap Project DO1-383/18.12.2020 of the Ministry of Education and Science of the Republic of Bulgaria. IA acknowledges financial support from the Spanish ‘Ministerio de Ciencia e Innovación’ (MCINN) through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía-CSIC (SEV-2017-0709). Acquisition and reduction of the POLAMI data was supported in part by MICINN through grants AYA2016-80889-P and PID2019-107847RB-C44. The POLAMI observations were carried out at the IRAM 30m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Published: 2021

21. The dual nature of blazar fast variability. Space and ground observations of S5 0716+714

Author: F. D'Ammando, D. Carosati, Evgeni Semkov, D. O. Mirzaqulov, Lorand A. Sigua, Giacomo Bonnoli, Katsura Matsumoto, M. Nakamura, Valeri M. Larionov, V. Dhiman, A. Di Maggio, M. I. Carnerero, M. Villata, J. M. Lopez, A. A. Nikiforova, A. A. Vasilyev, T. Pursimo, An-Li Tsai, Sh. A. Ehgamberdiev, Raúl Mújica, G. A. Borman, C. M. Raiteri, Sofia O. Kurtanidze, J. A. Acosta-Pulido, Alessandro Marchini, A. V. Zhovtan, Alok C. Gupta, M. G. Nikolashvili, I. S. Troitsky, David Hiriart, L. Stiaccini, C. Lin, G. V. Baida, D. N. Okhmat, T. Sakamoto, Barbara Balmaverde, Erika Benítez, Wen Ping Chen, Omar M. Kurtanidze, Givi N. Kimeridze, N. Rizzi, J. Otero-Santos, National Aeronautics and Space Administration (US), Ministry of Education, Youth and Science (Bulgaria), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Shota Rustaveli National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), and Universidad Nacional Autónoma de México
Subjects: active [Galaxies], galaxies: active, galaxies: jets, galaxies: BL Lacertae objects: general, galaxies: BL Lacertae objects: individual: S5 0716+714, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Space (mathematics), 01 natural sciences, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Mathematical physics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, general [BL Lacertae objects], Astronomy and Astrophysics, BL Lacertae objects: general, Galaxies: active, DUAL (cognitive architecture), Space and Planetary Science, Galaxies: jets, BL Lacertae objects: individual: S5 0716+714, individual: S5 0716+714 [BL Lacertae objects], jets [Galaxies], Astrophysics - High Energy Astrophysical Phenomena
Abstract: Full list of authors: Raiteri, C. M.; Villata, M.; Carosati, D.; Benítez, E.; Kurtanidze, S. O.; Gupta, A. C.; Mirzaqulov, D. O.; D'Ammando, F.; Larionov, V. M.; Pursimo, T.; Acosta-Pulido, J. A.; Baida, G. V.; Balmaverde, B.; Bonnoli, G.; Borman, G. A.; Carnerero, M. I.; Chen, W. -P.; Dhiman, V.; Di Maggio, A.; Ehgamberdiev, S. A.; Hiriart, D.; Kimeridze, G. N.; Kurtanidze, O. M.; Lin, C. S.; Lopez, J. M.; Marchini, A.; Matsumoto, K.; Mujica, R.; Nakamura, M.; Nikiforova, A. A.; Nikolashvili, M. G.; Okhmat, D. N.; Otero-Santos, J.; Rizzi, N.; Sakamoto, T.; Semkov, E.; Sigua, L. A.; Stiaccini, L.; Troitsky, I. S.; Tsai, A. L.; Vasilyev, A. A.; Zhovtan, A. V., Blazar S5 0716+714 is well-known for its short-term variability, down to intraday time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December-2020 January and analyse the object fast variability with unprecedented sampling. Supporting observations by the Whole Earth Blazar Telescope Collaboration in B, V, R, and I bands allow us to investigate the spectral variability during the TESS pointing. The spectral analysis is further extended in frequency to the UV and X-ray bands with data from the Neil Gehrels Swift Observatory. We develop a new method to unveil the shortest optical variability time-scales. This is based on progressive de-trending of the TESS light curve by means of cubic spline interpolations through the binned fluxes, with decreasing time bins. The de-trended light curves are then analysed with classical tools for time-series analysis (periodogram, autocorrelation, and structure functions). The results show that below 3 d there are significant characteristic variability time-scales of about 1.7, 0.5, and 0.2 d. Variability on time-scales $\lesssim 0.2$ d is strongly chromatic and must be ascribed to intrinsic energetic processes involving emitting regions, likely jet substructures, with dimension less than about 10-3 pc. In contrast, flux changes on time-scales $\gtrsim 0.5$ d are quasi-achromatic and are probably due to Doppler factor changes of geometric origin. © 2020 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society, The Astronomical Observatory of the University of Siena thanks the friend amateur astronomers Massimo Conti and Claudio Vallerani for their invaluable and unceasing contribution, essential for the performance of the observatory. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. This research has made use of NASA's Astrophysics Data System and of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. Based (partly) on data obtained with the STELLA robotic telescopes in Tenerife, an AIP facility jointly operated by AIP and IAC. This work is partly based upon observations carried out at the Observatorio Astronomico Nacional on the Sierra San Pedro Martir (OAN-SPM), Baja California, Mexico. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grantsDN18-13/2017, KP06-H28/3, and KP-06-PN38/4. KM acknowledges JSPS KAKENHI grant no. JP19K03930. SOK acknowledges financial support by Shota Rustaveli National Science Foundation of Georgia under contract PHDF-18-354. EB acknowledges support from DGAPAPAPIIT GRANT IN113320. GB acknowledges financial support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709).
Published: 2020

22. A New Multi-Wavelength Census of Blazars

Author: Matteo Bonato, M. Villata, C. M. Raiteri, G. de Zotti, M. I. Carnerero, and Alessandro Paggi
Subjects: QSOS, Active galactic nucleus, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, catalogs, 01 natural sciences, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Redshift, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract: Context:Blazars are the rarest and most powerful active galactic nuclei, playing a crucial and growing role in today multi-frequency and multi-messenger astrophysics. Current blazar catalogs, however, are incomplete and particularly depleted at low Galactic latitudes. Aims: We aim at augmenting the current blazar census to build a catalog of blazar candidates with homogeneous sky coverage that can provide candidate counterparts to unassociated gamma-ray sources, sources of high-energy neutrino emission, and ultra-high energy cosmic rays. Methods: Starting from the ALMA Calibrator Catalog we built a catalog of 1580 blazar candidates (ALMA Blazar Candidates, ABC) for which we collect multi-wavelength information. We also compared ABC sources with existing blazar catalogs. Results: The ABC catalogue fills the lack of low Galactic latitude sources in current blazar catalogues. ABC sources are significantly dimmer than known blazars in Gaia g band, and they appear bluer in SDSS and WISE colors. The majority of ABC sources (~ 90%) have optical spectra that classify them as QSO, while the remaining sources resulted galactic objects. ABC sources are similar in X-rays to known blazar, while in gamma-rays they are on average dimmer and softer, indicating a significant contribution of FSRQ sources. Making use of WISE colours, we classified 715 ABC sources as candidate gamma-ray blazar of different classes. Conclusions: We built a new catalogue of 1580 candidate blazars with a rich multi-wavelength data-set, filling the lack of low Galactic latitude sources in current blazar catalogues. This will be particularly important to identify the source population of high energy neutrinos or ultra-high energy cosmic rays. The data collected by the upcoming LSST surveys will provide a key tool to investigate the possible blazar nature of these sources., 53 pages, 32 figures, 6 tables. Accepted for publication on A&A
Published: 2020

23. 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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24. Quasi-periodic behaviour in the optical and γ-ray light curves of blazars 3C 66A and B2 1633+38

Author: C. Ballester Niebla, Elena G. Larionova, Paul S. Smith, N. Castro Segura, Valeri M. Larionov, E. N. Kopatskaya, M. Villata, Yu. V. Troitskaya, T. S. Grishina, M. I. Carnerero, A. A. Nikiforova, J. Becerra González, J. A. Acosta-Pulido, Pablo Peñil, G. A. Borman, Ivan S. Troitsky, Sergey S. Savchenko, C. M. Raiteri, D. A. Morozova, A. A. Vasilyev, and J. Otero-Santos
Subjects: Physics, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Polarimetry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Astrophysics, Correlation function (astronomy), Light curve, 01 natural sciences, law.invention, Telescope, Space and Planetary Science, Observatory, law, 0103 physical sciences, Blazar, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, BL Lac object
Abstract: We report on quasi-periodic variability found in two blazars included in the Steward Observatory Blazar Monitoring data sample: the BL Lac object 3C 66A and the Flat Spectrum Radio Quasar B2 1633+38. We collect optical photometric and polarimetric data in V and R bands of these sources from different observatories: St. Petersburg University, Crimean Astrophysical Observatory, WEBT-GASP, Catalina Real-Time Transient Survey, Steward Observatory, STELLA Robotic Observatory and Katzman Automatic Imaging Telescope. In addition, an analysis of the $\gamma$-ray light curves from $\textit{Fermi}$-LAT is included. Three methods are used to search for any periodic behaviour in the data: the Z-transform Discrete Correlation Function, the Lomb-Scargle periodogram and the Weighted Wavelet Z-transform. We find evidences of possible quasi-periodic variability in the optical photometric data of both sources with periods of $\sim$3 years for 3C 66A and $\sim$1.9 years for B2 1633+38, with significances between 3$\sigma$ and 5$\sigma$. Only B2 1633+38 shows evidence of this behaviour in the optical polarized data set at a confidence level of 2$\sigma$-4$\sigma$. This is the first reported evidence of quasi-periodic behaviour in the optical light curve of B2 1633+38. Also a hint of quasi-periodic behaviour is found in the $\gamma$-ray light curve of B2 1633+38 with a confidence level $\geqslant$2$\sigma$, while no periodicity is observed for 3C 66A in this energy range. We propose different jet emission models that could explain the quasi-periodic variability and the differences found between these two sources., Comment: Accepted for publication in MNRAS
Published: 2020

25. Multiwavelength Variability of BL Lacertae Measured with High Time Resolution

Author: Katsura Matsumoto, Ivan S. Troitsky, G. V. Baida, Evgeni Ovcharov, Yu. V. Troitskaya, Svetlana G. Jorstad, An-Li Tsai, Sh. A. Ehgamberdiev, M. I. Carnerero, Alan P. Marscher, V. Dhiman, S. O. Kurtanidze, D. A. Morozova, Karen E. Williamson, A. V. Zhovtan, Krista Lynne Smith, O. Vince, M. Villata, A. A. Nikiforova, M. Minev, J. J. Slater, H. Y. Hsiao, A. A. Vasilyev, A. Strigachev, Wen Ping Chen, C. M. Raiteri, Goran Damljanović, J. A. Acosta-Pulido, Antoniya Valcheva, Sunay Ibryamov, Evgeni Semkov, D. O. Mirzaqulov, Erika Benítez, Rumen Bachev, Elena G. Larionova, Thomas J. Balonek, David Hiriart, Alok C. Gupta, E. Zaharieva, Givi N. Kimeridze, Z. R. Weaver, D. J. Dougherty, M. G. Nikolashvili, Ryota Matsumura, Valeri M. Larionov, D. Carosati, T. S. Grishina, A. C. Sadun, Sergey S. Savchenko, V. Bozhilov, M. Stojanovic, O. M. Kurtanidze, N. Rizzi, M. Hart, G. A. Borman, Michael D. Joner, and E. N. Kopatskaya
Subjects: Physics, Active galactic nucleus, Swift Gamma-Ray Burst Mission, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics, Light curve, Polarization (waves), 01 natural sciences, Exoplanet, law.invention, Telescope, Space and Planetary Science, law, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Blazar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Fermi Gamma-ray Space Telescope
Abstract: In an effort to locate the sites of emission at different frequencies and physical processes causing variability in blazar jets, we have obtained high time-resolution observations of BL Lacertae over a wide wavelength range: with the Transiting Exoplanet Survey Satellite (TESS) at 6000–10000 Å with 2 minute cadence; with the Neil Gehrels Swift satellite at optical, UV, and X-ray bands; with the Nuclear Spectroscopic Telescope Array at hard X-ray bands; with the Fermi Large Area Telescope at γ-ray energies; and with the Whole Earth Blazar Telescope for measurement of the optical flux density and polarization. All light curves are correlated, with similar structure on timescales from hours to days. The shortest timescale of variability at optical frequencies observed with TESS is ∼0.5 hr. The most common timescale is 13 ± 1 hr, comparable with the minimum timescale of X-ray variability, 14.5 hr. The multiwavelength variability properties cannot be explained by a change solely in the Doppler factor of the emitting plasma. The polarization behavior implies that there are both ordered and turbulent components to the magnetic field in the jet. Correlation analysis indicates that the X-ray variations lag behind the γ-ray and optical light curves by up to ∼0.4 day. The timescales of variability, cross-frequency lags, and polarization properties can be explained by turbulent plasma that is energized by a shock in the jet and subsequently loses energy to synchrotron and inverse Compton radiation in a magnetic field of strength ∼3 G.
Published: 2020

26. Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry

Author: Vincenzo Ripepi, P. Gavras, M. Vaillant, Mathias Schultheis, László Molnár, E. Poujoulet, Mark Cropper, C. Babusiaux, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, A. de Torres, Aldo Dell'Oro, J. Castañeda, Z. Kostrzewa-Rutkowska, A. Bombrun, André Moitinho, Marcella Marconi, Rossella Cancelliere, M. Hauser, M. Ajaj, C. M. Raiteri, L. Eyer, Michał Pawlak, H. I. Siddiqui, C. Ducourant, Tatiana Muraveva, Tsevi Mazeh, A. Panahi, Federico Marocco, Stefano Bertone, D. Vicente, Patrick Charlot, A. Guerrier, R. De March, Mario Gai, J. Souchay, H. E. P. Lindstrøm, Nicoletta Sanna, Agnes Fienga, Giovanni Comoretto, Jon Marchant, A. Lorca, E. Utrilla, A. Garcia-Gutierrez, Ilaria Musella, L. Balaguer-Núñez, Leanne P. Guy, N. Leclerc, E. Brugaletta, A. Yoldas, Harry Enke, Rosanna Sordo, Zoltan Balog, H. E. Huckle, L. Palaversa, Monica Rainer, T. A. Lister, F. A. Jansen, Ruth Carballo, Alessandro Spagna, J. M. Carrasco, Mikael Granvik, Derek W. Morris, F. Julbe, A. Hutton, J. Osinde, D. W. Evans, M. van Leeuwen, M. Weiler, F. Thévenin, F. Torra, Iain A. Steele, Lorenzo Rimoldini, Alessandro Sozzetti, Francesca Fragkoudi, K. Janßen, O. L. Creevey, J. González-Núñez, T. Pauwels, R. Buzzi, Miguel García-Torres, S. Liao, G. Tauran, Lennart Lindegren, C. Fouron, Pierre Fernique, Céline Reylé, P. Di Matteo, E. Szegedi-Elek, F. Pailler, Stefan Jordan, Roberto Molinaro, Elisabetta Caffau, Federica Spoto, Felix Franke, D. Barbato, Isabelle Lecoeur-Taïbi, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, E. Livanou, W. Roux, X. Peñalosa Esteller, P. A. Palicio, J. H. J. de Bruijne, Sergi Blanco-Cuaresma, Deborah Busonero, F. Riclet, Conny Aerts, Georges Kordopatis, Guy Rixon, F. Solitro, Davide Massari, Mike Smith, D. Baines, Roberto Morbidelli, Gerry Gilmore, G. Plum, Alexey Mints, O. Marchal, Juan Zorec, Ángel Gómez, C. A. Stephenson, Michael Davidson, C. Fabricius, E. Licata, Sergio Messina, Laszlo Szabados, M. Biermann, A. Garofalo, G. Holland, F. De Angeli, Andreas Korn, E. Anglada Varela, Grigori Fedorets, S. Girona, E. Gerlach, Antonella Vallenari, M. Riello, Łukasz Wyrzykowski, Damien Ségransan, F. Taris, L. Bramante, Alberto Cellino, S. Regibo, Andrej Prsa, M. Sarasso, E. Poggio, W. Löffler, Paolo Giacobbe, Jordi Portell, Elisa Distefano, Eric Slezak, I. Bellas-Velidis, Nicolas Rambaux, E. Balbinot, J.-B. Delisle, Maroussia Roelens, E. Salguero, P. de Teodoro, E. van Dillen, Y. Lebreton, Francois Mignard, Sergei A. Klioner, Ulrich Bastian, N. Samaras, G. Orrù, R. E. de Souza, P. Esquej, Paul J. McMillan, A. C. Lanzafame, Sébastien Lambert, Beatrice Bucciarelli, Jose M Hernandez, M. Bernet, S. Ragaini, Gisella Clementini, A. F. Mulone, Ludovic Delchambre, C. Panem, Eric Gosset, P. David, M. Garcia-Reinaldos, Ana Ulla, F. Crifo, J. Guiraud, Mariateresa Crosta, L. Chaoul, C. Diener, Carlos Dafonte, Karri Muinonen, Alex Lobel, J.-L. Bassilana, Maria Süveges, Isabella Pagano, Dimitri Pourbaix, D. Eappachen, M. Haywood, R. Drimmel, Y. Viala, S. Voutsinas, D. Semeux, William Thuillot, N. A. Walton, Paolo Montegriffo, A. Abreu Aramburu, C. Fabre, H. Zhao, Alessandro Bressan, S. Bouquillon, Sanjeev Khanna, T. Lebzelter, N. Tonello, L. Siltala, M. G. Lattanzi, C. Crowley, P. Yvard, Carme Jordi, Elena Pancino, E. del Pozo, Jan Rybizki, Nami Mowlavi, C. Barache, Morgan Fouesneau, J. De Ridder, Ugo Becciani, Martin Altmann, F. van Leeuwen, P. M. Marrese, M. A. Álvarez, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Caroline Soubiran, C. P. Murphy, A. M. Piersimoni, Alessandra Mastrobuono-Battisti, Peter G. Jonker, A. Sagristà Sellés, T. Roegiers, S. Marinoni, Johannes Sahlmann, Rene Andrae, P. Sartoretti, G. Altavilla, Raphael Guerra, F. X. Pineau, M. Segol, T. Prusti, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Andrea Chiavassa, Laurent Chemin, C. Turon, H. Steidelmüller, Douglas J. Marshall, A. G. Butkevich, Alberto Riva, P. de Laverny, Simchon Faigler, Laurent Galluccio, A. Mora, P. Re Fiorentin, C. Ordénovic, J. F. Le Campion, A. Delgado, V. Sanchez Gimenez, M. David, G. Sadowski, R. L. Smart, A. Masip, Laia Casamiquela, R. Messineo, R. Mor, J. Bakker, C. Dolding, J. M. Martín-Fleitas, S. Diakite, Coryn A. L. Bailer-Jones, D. Souami, P. Madrero Pardo, Martin A. Barstow, David Teyssier, Ummi Abbas, Jesus Salgado, Paolo Tanga, A. Burlacu, O. Vanel, Ulrike Heiter, Daniel Hestroffer, Sebastian L. Hidalgo, H. E. Delgado, Alberto Krone-Martins, C. Robin, Kevin Benson, Christos Siopis, S. Managau, P. Burgess, Tomaz Zwitter, M. M. S. Marcos Santos, S. Cowell, J. L. Halbwachs, Xavier Luri, Antti Penttilä, R. Geyer, Minia Manteiga, Yassine Damerdji, Nigel Hambly, S. Bartolomé, J. Álvarez Cid-Fuentes, P. Osborne, J. Juaristi Campillo, Mark Taylor, Richard I. Anderson, Y. Le Fustec, Thierry Morel, T. Cornez, Krzysztof A. Rybicki, L. Pulone, N. Bauchet, Pierre Kervella, C. Zurbach, Alfred Castro-Ginard, Frédéric Arenou, P. Ramos, Robert G. Mann, Annie C. Robin, J. C. Segovia, M. Barros, Hector Canovas, D. L. Harrison, Y. Lasne, L. Noval, David Hobbs, E. F. del Peloso, P. Castro Sampol, Yves Fremat, F. De Luise, Daniel Michalik, P. J. Richards, L. Karbevska, N. Hładczuk, K. Kruszyńska, T. Boch, Sofia Randich, A. G. A. Brown, C. Pagani, L. Martin Polo, M. Ramos-Lerate, Krzysztof Nienartowicz, Eduard Masana, E. Racero, E. Fraile, Marc Audard, N. Robichon, Luciana Bianchi, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Jérôme Berthier, Despina Hatzidimitriou, R. Gutiérrez-Sánchez, M. Fabrizio, I. Gonzalez-Santamaria, A. Dapergolas, P. Panuzzo, Benoit Carry, Francesca Figueras, R. Blomme, Elmé Breedt, D. Munoz, Diego Bossini, G. Busso, D. Katz, Simon Hodgkin, Ennio Poretti, N. Brouillet, Marco Castellani, Nicholas Rowell, Arnaud Siebert, M. Romero-Gómez, Shay Zucker, W. van Reeven, A. Kochoska, G. Giuffrida, Eva Sciacca, T. Carlucci, L. M. Sarro, M. I. Carnerero, Amina Helmi, D. Garabato, B. Holl, Michele Bellazzini, L. Rohrbasser, Teresa Antoja, J. Torra, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, C. Nicolas, Silvio Leccia, N. Cheek, Uwe Lammers, Ramachrisna Teixeira, Techniche Universtât Desden, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lund Observatory, Lund University [Lund], Zentrum für astronomie, Universität Heidelberg [Heidelberg], Department of nuclear medicine, Haukeland University Hospital, University of Bergen (UiB)-University of Bergen (UiB), Merck Serono S.A [Geneva Research Center], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Gaia Collaboration, Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos Universidad de Barcelona, MDM-2014-0369, Centro de Excelencia Científica Severo Ochoa, Instituto de Ciencias del Cosmos de la Universidad de Barcelona, SEV2015-0493, Deliste, J. B. [0000-0001-5844-9888], Sozzeti, A. [0000-0002-7504-365X], Forderung der wissenschaftlichen Forschung (FWF), Belgian federal Science Policy Office (BELSPO), Hertha Firnberg Programme, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Comite Francais d'Evaluation de la Cooperation Universitaire et Scientifique avec le Bresil (COFECUB), National Natural Science Foundation of China (NSFC), China Scholarship Council (CSC), European Commission (EC), European Research Council (ERC), Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Istituto Nazionale di Astrofisica (INAF), Netherlands Research School for Astronomy (NOVA), Fundacao para a Ciencia e a Tecnologia (FCT), Agencia Estatal de Investigación (AEI), European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR), Narodowe Centrum Nauki (NCN), Slovenian Research Agency, Swedish National Space Agency (SNSA), United Kingdom Science and Technology Facilities Council (STFC), Universitat de Barcelona (UB), Generalitat de Catalunya, Xunta de Galicia, Universidad de Cantabria, ITA, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Astronomy, and Kapteyn Astronomical Institute
Subjects: Data Analysis, Solar System, Astronomy, kinematics and dynamics, virgo cluster, Astrophysics, 01 natural sciences, bar, Astronomi, astrofysik och kosmologi, large-magellanic-cloud, Methods, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Physics, Astrophysics of Galaxies, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, VIRGO CLUSTER, Kinematics and Dynamics, Amplitude, kinematics, Physical Sciences, MILKY-WAY, astrometry, Galaxy: kinematics and dynamics, PROPER MOTION, Proper motion, perturbation, proper motions, reference systems, methods: data analysis, Astrophysics - Astrophysics of Galaxies, FOS: Physical sciences, Context (language use), proper motion, Astronomy & Astrophysics, MASS, Computer Science::Digital Libraries, Gravitational potential, Acceleration, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, data analysis [methods], Vector spherical harmonics, KINEMATICS, distance, milky-way, Science & Technology, PERTURBATION, 010308 nuclear & particles physics, Astronomy and Astrophysics, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, Physics::History of Physics, BAR, Galaxy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), DISTANCE, mass, LARGE-MAGELLANIC-CLOUD
Abstract: Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions., Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution., Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate., Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 +/- 0.16) x 10(-10) m s(-2) (or 7.33 +/- 0.51 km s(-1) Myr-1) towards alpha = 269.1 degrees +/- 5.4 degrees, delta = -31.6 degrees +/- 4.1 degrees, corresponding to a proper motion amplitude of 5.05 +/- 0.35 mu as yr(-1). This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 mu as yr(-1).
Published: 2020
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27. Update on the Multi-Frequency Monitoring of Blazars with Medicina and Noto

Author: Carla Buemi, M. Villata, P. Cassaro, Simona Righini, Marcello Giroletti, Andrea Orlati, Grazia Umana, Monica Orienti, Uwe Bach, Corrado Trigilio, C. M. Raiteri, and Paolo Leto
Subjects: Computer science, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Luminosity, Black hole, Space and Planetary Science, Spectral energy distribution, Radio frequency, Blazar, Energy (signal processing), Radio wave
Abstract: The Medicina and Noto radiotelescopes have been employed for over 14 years to monitor the flux density variations of a vast sample of blazars at different radio frequencies. Radio data are essential components of blazar spectral energy distribution (SED, spanning from radio waves to gamma rays), whose trend with luminosity and shape changes provide decisive information on the physics of extra-galactic jets and, eventually, on the mechanism extracting energy from the central black hole in radio-loud AGN. Observations presently carried out at 5, 8 and 24 GHz have taken advantage of the continually evolving control system installed at the antennas. A new, batch-wise analysis tool was also produced, in order to easily handle and reduce the datasets acquired in monthly sessions. We here describe the latest developments and achievements.
Published: 2018
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28. The beamed jet and quasar core of the distant blazar 4C 71.07

Author: A. Di Paola, Evgeni Ovcharov, Yu. V. Troitskaya, Sergey S. Savchenko, A. A. Arkharov, N. V. Efimova, V. Bozhilov, M. G. Nikolashvili, Sunay Ibryamov, Elena G. Larionova, Manash R. Samal, P. Calcidese, I. Agudo, Marcello Giroletti, Givi N. Kimeridze, J. L. Gomez, Carolina Casadio, Anne Lähteenmäki, C. M. Raiteri, Alan P. Marscher, Valeri M. Larionov, Uwe Bach, D. Carosati, P. Romano, M. Minev, G. A. Borman, A. C. Sadun, Lorand A. Sigua, E. N. Kopatskaya, S. Vercellone, Joseph Moody, Goran Damljanović, Evgeni Semkov, D. O. Mirzaqulov, S. Baitieri, M. Villata, A. Strigachev, O. M. Kurtanidze, Helen Jermak, S. A. Klimanov, R. Bachev, Stoyanka Peneva, Wen Ping Chen, Walter Boschin, S. G. Jorstad, Sol N. Molina, D. A. Morozova, Iain A. Steele, O. Vince, M. S. Butuzova, T. S. Grishina, V. T. Doroshenko, Sofia O. Kurtanidze, M. I. Carnerero, J. A. Acosta-Pulido, L. Slavcheva-Mihova, Simona Righini, N. Rizzi, S. V. Nazarov, Boyko Mihov, Ivan S. Troitsky, Sh. A. Ehgamberdiev, Merja Tornikoski, A. A. Nikiforova, Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, Aalto University, Istituto Nazionale di Astrofisica, Bulgarian National Science Fund, Ministry of Education, Youth and Science (Bulgaria), Ministry of Education, Science and Technological Development (Serbia), Russian Science Foundation, and Shota Rustaveli National Science Foundation
Subjects: ACTIVE GALACTIC NUCLEI, RADIO-SOURCES, Quasars: individual: 4C 71.07, Astrophysics::High Energy Astrophysical Phenomena, jets [galaxies], Library science, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, The Republic, Observatory, 0103 physical sciences, ABSORPTION, Astrophysics::Solar and Stellar Astrophysics, SPECTRA, Bulgarian, 010303 astronomy & astrophysics, BLACK-HOLES, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Government, 010308 nuclear & particles physics, St petersburg, Astronomy and Astrophysics, Galaxies: active, Astrophysics - Astrophysics of Galaxies, language.human_language, Joint research, VARIABILITY, Work (electrical), 13. Climate action, Space and Planetary Science, Galaxies: jets, WEBT CAMPAIGN, Astrophysics of Galaxies (astro-ph.GA), individual: 4C 71.07 [quasars], active [galaxies], language, LUMINOSITY, ROTATIONS, Christian ministry, COMPLETE SAMPLE, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The object 4C 71.07 is a high-redshift blazar whose spectral energy distribution shows a prominent big blue bump and a strong Compton dominance. We present the results of a 2- yr multiwavelength campaign led by the Whole Earth Blazar Telescope (WEBT) to study both the quasar core and the beamed jet of this source. The WEBT data are complemented by ultraviolet and X-ray data from Swift, and by γ-ray data by Fermi. The big blue bump is modelled by using optical and near-infrared mean spectra obtained during the campaign, together with optical and ultraviolet quasar templates. We give prescriptions to correct the source photometry in the various bands for the thermal contribution, in order to derive the non-thermal jet flux. The role of the intergalactic medium absorption is analysed in both the ultraviolet and X-ray bands.We provide opacity values to deabsorb ultraviolet data, and derive a best-guess value for the hydrogen column density of Nbest H = 6.3 × 10 cmthrough the analysis of X-ray spectra.We estimate the disc and jet bolometric luminosities, accretion rate, and black hole mass. Light curves do not show persistent correlations among flux changes at different frequencies. We study the polarimetric behaviour and find no correlation between polarization degree and flux, even when correcting for the dilution effect of the big blue bump. Similarly, wide rotations of the electric vector polarization angle do not seem to be connected with the source activity.© 2019 The Author(s)., We acknowledge financial contribution from the agreement ASI-INAF n.2017-14-H.0 and from the contract PRIN-SKA-CTA-INAF 2016. PR and SV acknowledge contract ASI-INAF I/004/11/0. We acknowledge support by Bulgarian National Science Programme 'Young Scientists and Postdoctoral Students 2019', Bulgarian National Science Fund under grant DN18-10/2017 and National RI Roadmap Projects DO1-157/28.08.2018 and DO1-153/28.08.2018 of the Ministry of Education and Science of the Republic of Bulgaria. GD and OV gratefully acknowledge the observing grant support from the Institute of Astronomy and Rozhen National Astronomical Observatory, Bulgarian Academy of Sciences via bilateral joint research project 'Study of ICRF radio-sources and fast variable astronomical objects' (head -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. This research was partially supported by the Bulgarian National Science Fund of theMinistry of Education and Science under grants DN 08-1/2016, DN 18-13/2017, and KP-06-H28/3 (2018). 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 Extraterrestrische Physik. The St Petersburg University team acknowledges support from Russian Science Foundation grant no. 17-12-01029. The Abastumani team acknowledges financial support by the Shota Rustaveli National Science Foundation under contract FR/217950/16. This work was partly supported by the National Science Fund of the Ministry of Education and Science of Bulgaria under grant DN 08-20/2016, and by funds of the project RD-08-37/2019 of the University of Shumen. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clement Fillietroz-ONLUS, which is supported by the Regional Government of the Aosta Valley, the Town Municipality of Nus and the Unite des Communes valdotaines Mont-Emilius'. The research at the OAVdA was partially funded by two 'Research and Education' grants from Fondazione CRT
Published: 2019

29. 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

30. Unraveling the Complex Behavior of Mrk 421 with Simultaneous X-Ray and VHE Observations during an Extreme Flaring Activity in 2013 April

Author: Simonetta Puccetti, D. Dominis Prester, M. Makariev, Alice Donini, Sofia O. Kurtanidze, G. Bonnoli, Julian Sitarek, D. Dorner, Yoshiki Ohtani, J. Becerra González, S. Ventura, S. Ansoldi, L. Nogués, J. Besenrieder, A. Rugliancich, P. Munar-Adrover, Jose Luis Contreras, B. Jordan, I. Puljak, Pawel Gliwny, L. V. Larionova, L. Di Venere, Sunay Ibryamov, Abelardo Moralejo, M. I. Martínez, B. De Lotto, Juan Cortina, A. A. Mokrushina, E. Moretti, Kaya Mori, Maria Petropoulou, Elena G. Larionova, J. Rico, Juan Abel Barrio, Narek Sahakyan, A. Fattorini, C. Fruck, F. Del Puppo, F. Verrecchia, Victoria Moreno, Chiara Righi, M. V. Fonseca, Elina Lindfors, Justin D. Finke, D. A. Morozova, V. D'Elia, A. López-Oramas, M. G. Nikolashvili, John Hoang, Susumu Inoue, L. Maraschi, R. Paoletti, R. Reinthal, A. Strigachev, Saverio Lombardi, T. Schweizer, E. Do Souto Espiñeira, Tomislav Terzić, Ferdinando Giordano, Fabrizio Tavecchio, C. Nigro, B. Banerjee, Bernd Schleicher, A. Hahn, R. G. Chanishvili, Francesco Longo, M. Will, Shunsuke Sakurai, Ll. Font, Takeshi Oka, Davide Depaoli, Alan P. Marscher, L. Saha, D. Elsaesser, Antonio Stamerra, R. Carosi, G. Ceribella, Joni Tammi, V. Fallah Ramazani, D. Lelas, T. Guever, M. Teshima, J. M. Paredes, Dorota Sobczyńska, Zeljka Bosnjak, Chakali Eswaraiah, A. C. R. Readhead, G. Busetto, Jorge Otero-Santos, Mislav Baloković, J. L. Richards, R. A. Chigladze, Y. Chai, J. Kushida, Seiya Nozaki, Kari Nilsson, U. Barres de Almeida, L. Foffano, Ciro Bigongiari, Saša Mićanović, V. Vitale, Wen Ping Chen, P. Temnikov, T. Saito, Andrei Berdyugin, David H. Green, D. Strom, F. Di Pierro, E. N. Kopatskaya, Stefano Covino, D. Miceli, S. Gasparyan, D. Blinov, G. Maneva, E. Molina, S. G. Jorstad, T. Surić, M. Mariotti, I. Šnidarić, Satoshi Fukami, H. Kubo, M. Vazquez Acosta, R. López-Coto, Kazuma Ishio, Y. Iwamura, M. Gaug, A. Lamastra, A. C. Sadun, J. Herrera, G. Vanzo, Oscar Blanch, T. S. Grishina, Walter Max-Moerbeck, Anne Lähteenmäki, S. M. Colak, Valeri M. Larionov, C. M. Raiteri, C. Maggio, O. M. Kurtanidze, S. Cikota, D. Ninci, G. Ferrara, A. De Angelis, Rumen Bachev, Yu. V. Troitskaya, M. Minev, Georgi Latev, Elisa Bernardini, Other groups, L. Pavletić, Elisa Prandini, Goran Damljanović, Evgeni Semkov, M. Delfino, Wolfgang Rhode, Yusuke Suda, Massimo Persic, Carlo Vigorito, A. Berti, Paul S. Smith, K. Noda, Dario Hrupec, C. Leto, Victor A. Acciari, K. Nishijima, B. Machado de Oliveira Fraga, Mitsunari Takahashi, P. Peñil, L. Bellizzi, Serena Loporchio, Jose Miguel Miranda, N. Godinović, M. Strzys, Ashot Chilingarian, N. Giglietto, U. Colin, W. Bednarek, Simone Mender, Moritz Hütten, W. Bhattacharyya, I. Agudo, R. Mirzoyan, Louis Antonelli, Dominik Baack, P. Majumdar, G. M. Madejski, A. Arbet Engels, Vitaly Neustroev, J. W. Moody, Luca Tosti, M. Villata, D. Morcuende, N. Torres-Albà, I. Vovk, Jordi Delgado, H. C. Lin, Kevin Schmidt, Talvikki Hovatta, D. Hadasch, M. Palatiello, Y. Kajiwara, Francesco Dazzi, M. Mallamaci, O. Vince, M. Peresano, Yosuke Kobayashi, P. Da Vela, F. D'Ammando, K. Mannheim, R. J. García López, Ivan S. Troitsky, Tjark Miener, David Paneque, A. Biland, Marina Manganaro, P. G. Prada Moroni, Merja Tornikoski, Matteo Cerruti, M. López, Konstancja Satalecka, D. Mazin, Michele Doro, J. Barnes, F. Leone, M. Ribó, J. van Scherpenberg, A. Babić, Alessia Spolon, Léa Jouvin, Manasvita Joshi, Vassil Verguilov, Daniel Kerszberg, V. Ramakrishnan, D. Zarić, Tomohiro Inada, E. Colombo, M. Perri, M. Garczarczyk, Federal Ministry of Education and Research (Germany), Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Istituto Nazionale di Fisica Nucleare, Ministerio de Economía y Competitividad (España), European Commission, Department of Atomic Energy (India), Ministry of Education, Culture, Sports, Science and Technology (Japan), Japan Society for the Promotion of Science, Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, Croatian Science Foundation, University of Rijeka, German Research Foundation, National Centre for Research and Development (Poland), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, National Aeronautics and Space Administration (US), Department of Energy (US), Centre National de la Recherche Scientifique (France), Russian Science Foundation, Gordon and Betty Moore Foundation, John Templeton Foundation, Shota Rustaveli National Science Foundation, Comisión Nacional de Investigación Científica y Tecnológica (Chile), Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Magic, Collaboration, Other Groups And, Collaborator, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. A., Baack, D., Babic, A., Banerjee, B., De Almeida, U. B., Barrio, J. A., Gonzalez, J. B., Bednarek, W., Bellizzi, L. K., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Vela, P. D., Dazzi, F., Angelis, A. D., Lotto, B. D., Puppo, F. D., Delfino, M., Delgado, J., Depaoli, D., Pierro, F. D., Venere, L. D., Souto Espiñeira, E. D., Prester, D. D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Ramazani, V. F., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Lopez, R. J. G., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinovic, N., Green, D., Hadasch, D., Hahn, A., Hassan, T., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kajiwara, Y., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., De Oliveira Fraga, B. M., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Mender, S., Micanovic, S., Miceli, D., Miener, T., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletic, L., Peñil, P., Peresano, M., Persic, M., Moroni, P. G. P., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schleicher, B., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Spolon, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Scherpenberg, J. V., Vanzo, G., Acosta, M. V., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Petropoulou, M., Finke, J., D'Ammando, F., Balokovic, M., Madejski, G., Mori, K., Puccetti, S., Leto, C., Perri, M., Verrecchia, F., Villata, M., Raiteri, C. M., Agudo, I., Bachev, R., Berdyugin, A., Blinov, D. A., Chanishvili, R., Chen, W. P., Chigladze, R., Damljanovic, G., Eswaraiah, C., Grishina, T. S., Ibryamov, S., Jordan, B., Jorstad, S. G., Joshi, M., Kopatskaya, E. N., Kurtanidze, O. M., Kurtanidze, S. O., Larionova, E. G., Larionova, L. V., Larionov, V. M., Latev, G., Lin, H. C., Marscher, A. P., Mokrushina, A. A., Morozova, D. A., Nikolashvili, M. G., Semkov, E., Smith, P. S., Strigachev, A., Troitskaya, Y. V., Troitsky, I. S., Vince, O., Barnes, J., Guver, T., Moody, J. W., Sadun, A. C., Hovatta, T., Richards, J. L., Max-Moerbeck, W., Readhead, A. C. S., Lahteenmaki, A., Tornikoski, M., Tammi, J., Ramakrishnan, V., and Reinthal, R.
Subjects: Individual sources Mrk 421, Flux, Astrophysics, Blazar, 7. Clean energy, 01 natural sciences, Imaging Atmospheric Cherenkov observations, Gamma-ray, Active galaxie, Relativistic jet, MAGIC (telescope), BL lacertae objects, BL Lacertae objects, Blazars, Active galaxies, Markarian galaxies, Gamma-ray detectors, Gamma-rays, Relativistic jets, High energy astrophysics, Observational astronomy, 010303 astronomy & astrophysics, astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Gamma ray, X-ray, Markarian galaxie, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics and Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Individual sources Mrk 421, Imaging Atmospheric Cherenkov observations, MAGIC, BL Lacertae objects, Blazars, Active galaxies, Markarian galaxies, Gamma-ray detectors, Gamma-rays, Relativistic jets, High energy astrophysics, Observational astronomy, Plasmoid, Astrophysics::Cosmology and Extragalactic Astrophysics, BL Lacertae object, High energy astrophysic, 0103 physical sciences, Gamma-ray detector, 010308 nuclear & particles physics, Astronomy and Astrophysics, Magnetic reconnection, Light curve, MAGIC, 13. Climate action, Space and Planetary Science, ddc:520, High Energy Astrophysical Phenomena
Abstract: We report on a multiband variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 19. The study uses, among others, data from GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), Swift, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Large Area Telescope, Very Energetic Radiation Imaging Telescope Array System (VERITAS), and Major Atmospheric Gamma Imaging Cherenkov (MAGIC). The large blazar activity and the 43 hr of simultaneous NuSTAR and MAGIC/VERITAS observations permitted variability studies on 15 minute time bins over three X-ray bands (3-7 keV, 7-30 keV, and 30-80 keV) and three very-high-energy (VHE; >0.1 TeV) gamma-ray bands (0.2-0.4 TeV, 0.4-0.8 TeV, and >0.8 TeV). We detected substantial flux variations on multi-hour and sub-hour timescales in all of the X-ray and VHE gamma-ray bands. The characteristics of the sub-hour flux variations are essentially energy independent, while the multi-hour flux variations can have a strong dependence on the energy of the X-rays and the VHE gamma-rays. The three VHE bands and the three X-ray bands are positively correlated with no time lag, but the strength and characteristics of the correlation change substantially over time and across energy bands. Our findings favor multi-zone scenarios for explaining the achromatic/chromatic variability of the fast/slow components of the light curves, as well as the changes in the flux-flux correlation on day-long timescales. We interpret these results within a magnetic reconnection scenario, where the multi-hour flux variations are dominated by the combined emission from various plasmoids of different sizes and velocities, while the sub-hour flux variations are dominated by the emission from a single small plasmoid moving across the magnetic reconnection layer. © 2020. The American Astronomical Society. All rights reserved., The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-2-R, FPA2017-827 29-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, and FPA 201790566REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO-1153/28.08.2018 and the Academy of Finland grant No. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" SEV-20160588 and SEV-2015-0548, and Unidad de Excelencia "Maria de Maeztu" MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382, and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi-LAT.Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K..A..Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC; Italy) and the California Institute of Technology (USA). D.P. and A.B. are grateful to Amy Furniss and Wystan Benbow for providing the VERITAS VHE gamma-ray fluxes and for useful discussions about them. M.P. acknowledges support from the Lyman Jr. Spitzer Postdoctoral Fellowship and NASA Fermi grant No. 80NSSC18K1745., and J.F. is partially supported by NASA under contract S-15633Y. M.B. acknowledges support from NASA Headquarters under the NASA Earth and Space Science Fellowship Program (grant NNX14AQ07H) and the black hole Initiative at Harvard University, which is funded in part by the Gordon and Betty Moore Foundation (grant GBMF8273) and in part by the John Templeton Foundation. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants DN 18-13/2017, DN 18-10/2017, KP06-H28/3 (2018), and KP-06-PN38/1 (2019), as well as for the Spanish MIMECO (AYA2016-80889-P, RYC-2013-14511) and the IAA-CSIC "Severo Ochoa" program SEV2017-0709. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. The Abastumani team acknowledges financial support of the project FR/638/6-320/12 by the Shota Rustaveli National Science Foundation under contract 31/77. T.G. acknowledges support from Istanbul University (Project numbers 49429 and 48285), Bilim Akademisi (BAGEP program), and TUBITAK (project numbers 13AT100-431, 13AT100-466, and 13AT60-430). The Boston University effort was supported in part by NASA grants NNX12AO90G and NNX14AQ58G. Data from the Steward Observatory spectropolarimetric monitoring project were used in this paper. This program is supported by Fermi Guest Investigator grants NNX08AW56G, NNX09 AU10G, NNX12AO93G, and NNX15AU81G. The OVRO 40 m monitoring program is supported in part by NASA grants NNX08AW31G and NNX11A043G and NSF grants AST-0808050 and AST-1109911. The Metsahovi team acknowledges the support from the Academy of Finland to our observing projects (numbers 212656, 210338, 121148, and others). W.M. acknowledges support from CONICYT project Basal AFB-170002.
Published: 2020
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31. AGILE, Fermi, Swift, and GASP/WEBT multi-wavelength observations of the high-redshift blazar 4C +71.07 in outburst

Author: Andrea Bulgarelli, P. Romano, S. Vercellone, Carolina Casadio, Anne Lähteenmäki, Boyko Mihov, A. Strigachev, Emilia Järvelä, C. Pittori, G. A. Borman, F. Paoletti, Marco Tavani, José L. Gómez, Sergio Colafrancesco, U. Bach, V. Vittorini, I. Donnarumma, Valeri M. Larionov, Fabrizio Lucarelli, V. T. Doroshenko, J. A. Acosta-Pulido, Valentina Fioretti, L. Slavcheva-Mihova, Simona Righini, P. W. Cattaneo, E. N. Kopatskaya, O. M. Kurtanidze, C. M. Raiteri, S. A. Klimanov, M. Villata, Francesco Longo, M. S. Butuzova, F. D'Ammando, N. V. Efimova, F. Verrecchia, S. V. Nazarov, Evgeni Semkov, R. Bachev, M. I. Carnerero, D. O. Mirzaqulov, Sergey S. Savchenko, T. S. Grishina, G. Damljanovic, A. Morselli, A. Di Paola, M. Orienti, P. Munar-Adrover, L. V. Larionova, Marcello Giroletti, Sol N. Molina, Sh. A. Ehgamberdiev, D. A. Morozova, G. Piano, Merja Tornikoski, Arkady A. Arkharov, O. Vince, N. Parmiggiani, Yu. V. Troitskaya, I. Agudo, Vercellone, S., Romano, P., Piano, G., Vittorini, V., Donnarumma, I., Munar-Adrover, P., Raiteri, C. M., Villata, M., Verrecchia, F., Lucarelli, F., Pittori, C., Bulgarelli, A., Fioretti, V., Tavani, M., Acosta-Pulido, J. A., Agudo, I., Arkharov, A. A., Bach, U., Bachev, R., Borman, G. A., Butuzova, M. S., Carnerero, M. I., Casadio, C., Damljanovic, G., D'Ammando, F., Di Paola, A., Doroshenko, V. T., Efimova, N. V., Ehgamberdiev, S. A., Giroletti, M., Gómez, J. L., Grishina, T. S., Järvelä, E., Klimanov, S. A., Kopatskaya, E. N., Kurtanidze, O. M., Lähteenmäki, A., Larionov, V. M., Larionova, L. V., Mihov, B., Mirzaqulov, D. O., Molina, S. N., Morozova, D. A., Nazarov, S. V., Orienti, M., Righini, S., Savchenko, S. S., Semkov, E., Slavcheva-Mihova, L., Strigachev, A., Tornikoski, M., Troitskaya, Y. V., Vince, O., Cattaneo, P. W., Colafrancesco, S., Longo, F., Morselli, A., Paoletti, F., Parmiggiani, N., ITA, Academy of Sciences Republic of Uzbekistan, Russian Science Foundation, Bulgarian Academy of Sciences, Agenzia Spaziale Italiana, Ministerio de Economía y Competitividad (España), Ministry of Education, Science and Technological Development (Serbia), Osservatorio Astronomico di Brera, Osservatorio Astronomico Roma, ASI Science Data Center, Autonomous University of Barcelona, Osservatorio Astronomico di Torino, INAF/IASF Bologna, Università di Roma Tor Vergata, Instituto de Astrofísica de Canarias, CSIC, RAS - Pulkovo Astronomical Observatory, Max-Planck-Institut für Radioastronomie, Crimean Astrophysical Observatory, University of Belgrade, Universita di Bologna, Lomonosov Moscow State University, Academy of Sciences of the Republic of Uzbekistan, St. Petersburg State University, Metsähovi Radio Observatory, Georgian National Academy of Sciences, Istituto Nazionale di Fisica Nucleare (INFN), University of the Witwatersrand, Università Degli Studi di Trieste, Sapienza University of Rome, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University
Subjects: Galaxies [Gamma rays], Acceleration of particles, Relativistic processe, Radiation mechanisms: non-thermal, Astrophysics::High Energy Astrophysical Phenomena, Supermassive black holes [Quasars], FOS: Physical sciences, Galaxie [Gamma rays], Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, law, 0103 physical sciences, Gamma rays: Galaxies, Quasars: Individual: 4C +71.07, Quasars: Supermassive black holes, Relativistic processes, Astronomy and Astrophysics, Space and Planetary Science, Blazar, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, non-thermal [Radiation mechanisms], 010308 nuclear & particles physics, Order (ring theory), Quasar, Astronomy and Astrophysic, Acceleration of particle, Redshift, Supermassive black hole [Quasars], Spectral energy distribution, Individual: 4C +71.07 [Quasars], Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing), Flare, Fermi Gamma-ray Space Telescope
Abstract: Context. The flat-spectrum radio quasar 4C +71.07 is a high-redshift (z = 2.172), γ-loud blazar whose optical emission is dominated by thermal radiation from the accretion disc. Aims. 4C +71.07 has been detected in outburst twice by the AGILE γ-ray satellite during the period from the end of October to mid-November 2015, when it reached a γ-ray flux of the order of F(E > 100 MeV)=(1.2 ± 0.3)×10 photons cm s and F(E > 100 MeV)=(3.1 ± 0.6)×10 photons cm s, respectively, allowing us to investigate the properties of the jet and the emission region. Methods. We investigated its spectral energy distribution by means of almost-simultaneous observations covering the cm, mm, near-infrared, optical, ultraviolet, X-ray, and γ-ray energy bands obtained by the GASP-WEBT Consortium and the Swift, AGILE, and Fermi satellites. Results. The spectral energy distribution of the second γ-ray flare (whose energy coverage is more dense) can be modelled by means of a one-zone leptonic model, yielding a total jet power of about 4 × 10 erg s. Conclusions. During the most prominent γ-ray flaring period our model is consistent with a dissipation region within the broad-line region. Moreover, this class of high-redshift, flat-spectrum radio quasars with high-mass black holes might be good targets for future γ-ray satellites such as e-ASTROGAM. © ESO 2019., AGILE is an ASI space mission developed with programmatic support by INAF and INFN. We acknowledge partial support through the ASI grant no. I/028/12/0. SV and PR acknowledge contract ASI-INAF I/004/11/0 and INAF/IASF Palermo where most of the work was carried out. SV acknowledges financial contribution from the agreement ASI-INAF no. 2017-14-H.0. Part of this work is based on archival data, software, or online services provided by the ASI SPACE SCIENCE DATA CENTER (ASI-SSDC). SV and PR thank Leonardo Barzaghi and Sara Baitieri for useful discussions. The Osservatorio di Torino team acknowledges the financial contribution from the agreement ASI-INAF No. 2017-14-H.0 and from the contract PRIN-SKA-CTA-INAF 2016. OMK acknowledges financial support from the Shota Rustaveli National Science Foundation under contract FR/217950/16 and grants NSFC11733001, NSFCU1531245. IA acknowledges support from a Ramón y Cajal grant of the Ministerio de Economía y Compet-itividad (MINECO) of Spain. The research at the IAA–CSIC was supported in part by the MINECO through grants AYA2016–80889–P, AYA2013–40825–P, and AYA2010–14844, and by the regional government of Andalucía through grant P09–FQM–4784. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). Calar Alto Observatory is jointly operated by the MPIA and the IAA-CSIC. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grant DN 08-1/2016. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. AZT-24 observations are made within an agreement among the Pulkovo, Rome, and Teramo observatories. GD and OV gratefully acknowledge the observing grant support from the Institute of Astronomy and Rozhen National Astronomical Observatory, Bulgaria Academy of Sciences, via bilateral joint research project “Observations of ICRF radio-sources visible in optical domain” (PI G. Damljanovic). This work is a part of Project 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 Maidanak Observatory team acknowledges support from Uzbekistan Academy of Sciences grants No. F2-FA-F027 and F.4-16.
Published: 2019

32. Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013-2017

Author: Manasvita Joshi, Omar M. Kurtanidze, Katsura Matsumoto, Kozo Sadakane, Erika Benítez, Alan P. Marscher, O. Vince, Sebastian Kiehlmann, Rumen Bachev, Evgeni Ovcharov, Yu. V. Troitskaya, Talvikki Hovatta, Boyko Mihov, Givi N. Kimeridze, S. V. Nazarov, Arkady A. Arkharov, T. Pursimo, Joseph Moody, A. Giunta, Ivan S. Troitsky, Goran Damljanović, C. Espinosa, A. Fuentes, Yu. V. Sotnikova, N. Castro-Segura, Sol N. Molina, Evgeni Semkov, D. O. Mirzaqulov, M. I. Carnerero, Walter Boschin, M. G. Nikolashvili, T. V. Mufakharov, G. Rodríguez-Coira, Valeri M. Larionov, P. Calcidese, Walter Max-Moerbeck, D. A. Morozova, Sergey S. Savchenko, M. Mingaliev, D. Carosati, W. P. Chen, A. C. Sadun, A. A. Vasilyev, G. V. Baida, S. G. Jorstad, A. Strigachev, David Hiriart, N Okhmat, Juan Echevarria, Lorand A. Sigua, Paul S. Smith, F. D'Ammando, L. Slavcheva-Mihova, Joni Tammi, N. V. Efimova, C. S. Lin, E. N. Kopatskaya, Raul Michel, F. Pinna, B. McBreen, Iain A. Steele, N. Rizzi, Clemens Thum, Mark Gurwell, C. Protasio, M. Villata, J. M. Ohlert, J. A. Acosta-Pulido, Manash R. Samal, Sh. A. Ehgamberdiev, I. Agudo, Merja Tornikoski, K. S. Kuratov, Anthony C. S. Readhead, A. A. Nikiforova, Michael P. Malmrose, J. L. Gomez, B. Jordan, M. Minev, T. A. Polakis, A. Di Paola, L. V. Larionova, Carolina Casadio, Anne Lähteenmäki, Elena G. Larionova, Bozhilov, C. Lázaro, Helen Jermak, F. J. Redondo-Lorenzo, G. A. Borman, Rodrigo Reeves, Sofia O. Kurtanidze, M. S. Butuzova, Brian A. Skiff, T. S. Grishina, T. J. Pearson, C. M. Raiteri, Bulgarian National Science Fund, Shota Rustaveli National Science Foundation, Russian Science Foundation, Ministry of Education, Science and Technological Development (Serbia), Universidad Nacional Autónoma de México, Smithsonian Institution, Academia Sinica (Taiwan), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), WEBT, OVRO Team, Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, Aalto University, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: TELESCOPE, Astrophysics::High Energy Astrophysical Phenomena, jets [galaxies], nuclei [galaxies], Library science, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, individual: CTA 102 [galaxies], 01 natural sciences, FERMI, Observatory, 0103 physical sciences, Bulgarian, Aerospace, 010303 astronomy & astrophysics, SCALE, Physics, CALIBRATION, High Energy Astrophysical Phenomena (astro-ph.HE), SWIFT, 010308 nuclear & particles physics, business.industry, Astronomy and Astrophysics, galaxies: jets, gamma-rays: general, radiation mechanisms: non-thermal, non-thermal [radiation mechanisms], Monitoring program, BLAZARS, language.human_language, VARIABILITY, Work (electrical), 13. Climate action, Space and Planetary Science, High energy accelerator, FLARES, language, RADIATION, OBJECTS, galaxies: individual: cta 102, galaxies: nuclei, business, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Administration (government), Research center, general [gamma-rays]
Abstract: We present a multiwavelength study of the flat-spectrum radio quasar CTA 102 during 2013-2017. We use radio-to-optical data obtained by the Whole Earth Blazar Telescope, 15 GHz data from the Owens Valley Radio Observatory, 91 and 103 GHz data from the Atacama Large Millimeter Array, near-infrared data from the Rapid Eye Monitor telescope, as well as data from the Swift (optical-UV and X-rays) and Fermi (γ -rays) satellites to study flux and spectral variability and the correlation between flux changes at different wavelengths. Unprecedented γ -ray flaring activity was observed during 2016 November-2017 February, with four major outbursts. A peak flux of (2158 ± 63) × 10−8 ph cm−2 s−1, corresponding to a luminosity of (2.2 ± 0.1) × 1050 erg s−1, was reached on 2016 December 28. These four γ -ray outbursts have corresponding events in the near-infrared, optical, and UV bands, with the peaks observed at the same time. A general agreement between X-ray and γ -ray activity is found. The γ -ray flux variations show a general, strong correlation with the optical ones with no time lag between the two bands and a comparable variability amplitude. This γ -ray/optical relationship is in agreement with the geometrical model that has successfully explained the low-energy flux and spectral behaviour, suggesting that the long-term flux variations are mainly due to changes in the Doppler factor produced by variations of the viewing angle of the emitting regions. The difference in behaviour between radio and higher energy emission would be ascribed to different viewing angles of the jet regions producing their emission. © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society, The data collected by the WEBT collaboration are stored in the WEBT archive at the Osservatorio Astrofisico di Torino INAF (http://www.oato.inaf.it/blazars/webt/); for questions regarding their availability, contact the WEBT President Massimo Villata(massimo.villata@inaf.it).We acknowledge financial contribution from the agreementASI-INAFn. 2017-14-H.0 and from the contract PRIN-SKA-CTA-INAF 2016. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grants DN 08-1/2016, DN 18-13/2017, and KP-06-H28/3 (2018). 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 Extraterrestrische Physik. The Abastumani team acknowledges financial support by the Shota Rustaveli National Science Foundation under contract FR/217554/16. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. GD and OV gratefully acknowledge the observing grant support from the Institute of Astronomy and Rozhen National Astronomical Observatory, Bulgarian Academy of Sciences, via bilateral joint research project 'Study of ICRF radio-sources and fast variable astronomical objects' (head -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. JE is indebted to DGAPA (Universidad Nacional Autonoma de M ' exico) for financial support, PAPIIT project IN114917. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. Data from the Steward Observatory blazar monitoring project were used. This program is supported by NASA/Fermi Guest Investigator grants NNX12AO93G and NNX15AU81G. We acknowledge support by Bulgarian National Science Programme 'Young Scientists and Postdoctoral Students 2019', Bulgarian National Science Fund under grant DN18-10/2017 and National RI Roadmap Projects DO1-157/28.08.2018 and DO1-153/28.08.2018 of the Ministry of Education and Science of the Republic of Bulgaria. This publication makes use of data obtained at Mets ahovi Radio Observatory, operated by Aalto University in Finland. The Astronomical Observatory of the Autonomous Region of theAostaValley (OAVdA) is managed by the Fondazione Clment Fillietroz-ONLUS, which is supported by the Regional Government of the Aosta Valley, the TownMunicipality of Nus and the 'Unit des Communes valdtaines Mont-milius'. The research at the OAVdA was partially funded by two 'Research and Education' grants from Fondazione CRT. RR acknowledges support from CONICYT project Basal AFB-170002. MM and TM acknowledge support through the Russian Government Program of Competitive Growth of Kazan Federal University. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. The OVRO 40-m monitoring program is supported in part by NASA grants NNX08AW31G, NNX11A043G, and NNX14AQ89G, and NSF grants AST-0808050 and AST-1109911. We thank the Swift team for making these observations possible, the duty scientists, and science planners. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. FD thanks S. Covino for his help with the REM data reduction. This research has made use of data obtained from the high-energy Astrophysics Science Archive Research Center (HEASARC) provided by NASA's Goddard Space Flight Center.
Published: 2019
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33. 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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34. 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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35. Detection of persistent VHE gamma-ray emission from PKS 1510–089 by the MAGIC telescopes during low states between 2012 and 2017

Author: M. I. Martínez, P. Bangale, Sabrina Einecke, Jae-Young Kim, M. Makariev, Aaron Dominguez, Alicia Fattorini, G. Pedaletti, Ivica Puljak, Stefano Covino, B. De Lotto, Pierre Colin, J. Kushida, Jose Luis Contreras, Walter Max-Moerbeck, J. Becerra González, A. Arbet Engels, A. De Angelis, Vitaly Neustroev, M. Peresano, Chiara Righi, Juan Abel Barrio, D. Elsaesser, J. Palacio, Satoshi Masuda, J. E. Ward, Juan Cortina, Takashi Saito, Wrijupan Bhattacharyya, P. Temnikov, Sidika Merve Colak, Wolfgang Rhode, Giovanni Ceribella, I. Agudo, José L. Gómez, V. A. Acciari, Antonio Stamerra, D. Hadasch, D. Fidalgo, Camilla Maggio, Abelardo Moralejo, A. López-Oramas, P. Munar-Adrover, E. Moretti, Daniela Dorner, Pablo Peñil, Alexander Hahn, Dominik Baack, Gaia Vanzo, G. Maneva, E. Do Souto Espiñera, Joni Tammi, Adrian Biland, Elina Lindfors, Jürgen Besenrieder, C. M. Raiteri, Louis Antonelli, Sol N. Molina, Daniel Mazin, Ievgen Vovk, A. Berti, Francesco Dazzi, A. Fernández-Barral, K. Nishijima, Manuel Delfino, M. Gaug, R. J. García López, Nikola Godinovic, D. Dominis Prester, J. Rico, V. Ramakrishnan, Francesco Longo, Pratik Majumdar, D. Zarić, M. V. Fonseca, J. Herrera, T. Schweizer, Antonio Fuentes, Sebastian Kiehlmann, Marc Ribó, Ana Babić, A. Somero, Koji Noda, L. Maraschi, E. Prandini, Elisa Bernardini, P. Giammaria, V. Fallah Ramazani, John Hoang, Massimo Persic, Stefano Ansoldi, S. Paiano, Efthalia Traianou, Riccardo Paoletti, Tomislav Terzić, Ciro Bigongiari, Clemens Thum, B. Banerjee, P. G. Prada Moroni, Hidetoshi Kubo, C. Arcaro, J. van Scherpenberg, Karl Mannheim, I. Snidaric, Oscar Blanch, D. Kuveždić, Razmik Mirzoyan, U. Barres de Almeida, F. Leone, Carolina Casadio, Kari Nilsson, Damir Lelas, Anne Lähteenmäki, Masahiro Teshima, Stefan Cikota, M. Strzys, M. Will, Markus Garczarczyk, Dorota Sobczyńska, D. Ninci, M. Vazquez Acosta, Angela Sandrinelli, Cosimo Nigro, M. Nievas Rosillo, G. Ferrara, M. Minev, Victoria Moreno, G. Bonnoli, Kazuma Ishio, Yuki Iwamura, Susumu Inoue, Tarek M. Hassan, W. Bednarek, Fabrizio Tavecchio, Dario Hrupec, Luca Foffano, Ll. Font, L. Nogués, M. A. Lopez, Rodolfo Carosi, Mosè Mariotti, J. M. Paredes, J. R. Garcia, V. D'Elia, Saverio Lombardi, A. Rugliancich, Marina Manganaro, Ioannis Myserlis, D. Galindo, Merja Tornikoski, E. Molina, E. Colombo, Konstancja Satalecka, Michele Doro, Lab Saha, A. Niedzwiecki, David Paneque, D. Guberman, Jordi Delgado, F. Di Pierro, Talvikki Hovatta, P. Da Vela, Julian Sitarek, C. Fruck, N. Torres-Albà, Stefano Gallozzi, Jose Miguel Miranda, Alessandra Lamastra, T. Surić, Shimpei Tsujimoto, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Bednarek, W., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Ceribella, G., Cikota, S., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., DI Pierro, F., Do Souto Espiñera, E., Domínguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., García López, R. J., Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Kubo, H., Kushida, J., Kuveždić, D., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Oramas, A., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strzys, M., Surić, T., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Ward, J. E., Will, M., Zarić, D., Becerra González, J., Raiteri, C. M., Sandrinelli, A., Hovatta, T., Kiehlmann, S., Max-Moerbeck, W., Tornikoski, M., Lähteenmäki, A., Tammi, J., Ramakrishnan, V., Thum, C., Agudo, I., Molina, S. N., Gómez, J. L., Fuentes, A., Casadio, C., Traianou, E., Myserlis, I., Kim, J. -Y., Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Universitat de Barcelona, Federal Ministry of Education and Research (Germany), Max Planck Society, Ministerio de Economía y Competitividad (España), Swiss National Science Foundation, and Junta de Andalucía
Subjects: galaxies [Gamma rays], Astrophysics, 01 natural sciences, 7. Clean energy, jet [Galaxies], law.invention, Raigs gamma, law, Jets (Astrofísica), Broadband, 010303 astronomy & astrophysics, Physics, galaxies: active, galaxies: jets, gamma rays: galaxies, quasars: individual: PKS 1510-089, galaxie [Gamma rays], Gamma ray, Galaxies: active, 3. Good health, Magnetic field, Gamma rays: galaxies, Spectral energy distribution, Física nuclear, Galaxies: jets, Quasars: individual: PKS 1510-089, Astronomy and Astrophysics, Space and Planetary Science, Flare, Spectral shape analysis, active [Galaxies], astro-ph.GA, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 0103 physical sciences, individual: PKS 1510-089 [Quasars], Quasars, Quàsars, Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, Gamma rays, Quasar, Plasma, Astronomy and Astrophysic, Astrophysics - Astrophysics of Galaxies, Astrophysical jets, Astrophysics of Galaxies (astro-ph.GA), Galàxies actives, Active galaxies, ddc:520, jets [Galaxies]
Abstract: PKS 1510-089 is a flat spectrum radio quasar strongly variable in the optical and GeV range. To date, very high-energy (VHE, > 100 GeV) emission has been observed from this source either during long high states of optical and GeV activity or during short flares. Aims. We search for low-state VHE gamma-ray emission from PKS 1510-089. We characterize and model the source in a broadband context, which would provide a baseline over which high states and flares could be better understood. Methods. PKS 1510-089 has been monitored by the MAGIC telescopes since 2012. We use daily binned Fermi-LAT flux measurements of PKS 1510-089 to characterize the GeV emission and select the observation periods of MAGIC during low state of activity. For the selected times we compute the average radio, IR, optical, UV, X-ray, and gamma-ray emission to construct a low-state spectral energy distribution of the source. The broadband emission is modeled within an external Compton scenario with a stationary emission region through which plasma and magnetic fields are flowing. We also perform the emission-model-independent calculations of the maximum absorption in the broad line region (BLR) using two different models. Results. The MAGIC telescopes collected 75 hr of data during times when the Fermi-LAT flux measured above 1 GeV was below 3? × 10 -8 ? cm -2 ? s -1 , which is the threshold adopted for the definition of a low gamma-ray activity state. The data show a strongly significant (9.5¿) VHE gamma-ray emission at the level of (4.27 ± 0.61 stat ) × 10 -12 ? cm -2 ? s -1 above 150 GeV, a factor of 80 lower than the highest flare observed so far from this object. Despite the lower flux, the spectral shape is consistent with earlier detections in the VHE band. The broadband emission is compatible with the external Compton scenario assuming a large emission region located beyond the BLR. For the first time the gamma-ray data allow us to place a limit on the location of the emission region during a low gamma-ray state of a FSRQ. For the used model of the BLR, the 95% confidence level on the location of the emission region allows us to place it at a distance > 74% of the outer radius of the BLR. © ESO 2018., The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Exce-lencia “Severo Ochoa” SEV-2012-0234 and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382, and by the Brazilian MCTIC, CNPq and FAPERJ. IA acknowledges support from a Ramón y Cajal grant of the Ministerio de Economía, Industria, y Competitividad (MINECO) of Spain. Acquisition and reduction of the POLAMI and 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 Andalucía through grant P09-FQM-4784.
Published: 2018
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36. The Bright γ-ray Flare of 3C 279 in 2015 June: AGILE Detection and Multifrequency Follow-up Observations

Author: Alan P. Marscher, F. Verrecchia, E. N. Kopatskaya, Lorand A. Sigua, O. M. Kurtanidze, A. Morselli, Andrea Bulgarelli, M. Villata, F. Paoletti, P. W. Cattaneo, I. Donnarumma, Paolo Giommi, H. Y. Hsiao, C. Pittori, M. I. Carnerero, D. O. Mirzaqulov, Valeri M. Larionov, J. A. Acosta-Pulido, C. M. Raiteri, Sh. A. Ehgamberdiev, David Hiriart, L. V. Larionova, F. Longo, L. O. Takalo, Fabrizio Lucarelli, S. Vercellone, A. Strigachev, T. S. Grishina, V. Vittorini, Manash R. Samal, D. Carosati, Sofia O. Kurtanidze, G. A. Borman, Kari Nilsson, Givi N. Kimeridze, A. Goded, Marco Tavani, Wen Ping Chen, B. Spassov, M. Perri, S. Colafrancesco, Erika Benítez, Louis Antonelli, Svetlana G. Jorstad, D. A. Morozova, Simonetta Puccetti, Rumen Bachev, ITA, Pittori, C., Lucarelli, F., Verrecchia, F., Raiteri, C. M., Villata, M., Vittorini, V., Tavani, M., Puccetti, S., Perri, M., Donnarumma, I., Vercellone, S., Acosta-Pulido, J. A., Bachev, R., Benítez, E., Borman, G. A., Carnerero, M. I., Carosati, D., Chen, W. P., Ehgamberdiev, Sh. A., Goded, A., Grishina, T. S., Hiriart, D., Hsiao, H. Y., Jorstad, S. G., Kimeridze, G. N., Kopatskaya, E. N., Kurtanidze, O. M., Kurtanidze, S. O., Larionov, V. M., Larionova, L. V., Marscher, A. P., Mirzaqulov, D. O., Morozova, D. A., Nilsson, K., Samal, M. R., Sigua, L. A., Spassov, B., Strigachev, A., Takalo, L. O., Antonelli, L. A., Bulgarelli, A., Cattaneo, P., Colafrancesco, S., Giommi, P., Longo, F., Morselli, A., and Paoletti, and F.
Subjects: Physics, polarization, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Library science, Astronomy and Astrophysics, radiation mechanisms: non-thermal, non-thermal [radiation mechanisms], X-rays: general, 01 natural sciences, quasars: individual (3C 279), gamma rays: galaxies, Space and Planetary Science, Observatory, general [X-rays], active [galaxies], 0103 physical sciences, individual (3C 279) [quasars], Astrophysics::Solar and Stellar Astrophysics, galaxie [gamma rays], Christian ministry, 010303 astronomy & astrophysics
Abstract: We would like to acknowledge the financial support of ASI under contract to INAF:ASI 2014-049-R.0 dedicated to SSDC. Part of this work is based on archival data, software, or online services provided by the ASI SSDC. The research at Boston University was supported by National Science Foundation grant AST-1615796 and NASA Swift Guest Investigator grant 80NSSC17K0309. This research was partially supported by the Bulgarian National Science Fund of the Ministry of Education and Science under grant DN 08-1/2016. 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 Extraterrestrische Physik. The St. Petersburg University team acknowledges support from Russian Science Foundation grant 17-12-01029. This article is partly based on observations made with the telescope IAC80 operated by the Instituto de Astrofisica de Canarias in the Spanish Observatorio del Teide on the island of Tenerife. The IAC team acknowledges the support from the group of support astronomers and telescope operators of the Observatorio del Teide. Based (partly) on data obtained with the STELLA robotic telescopes in Tenerife, an AIP facility jointly operated by AIP and IAC. This work is partially based upon observations carried out at the Observatorio Astronomico Nacional on the Sierra San Pedro Martir (OAN-SPM), Baja California, Mexico. C.P., V.V. and M. T. also thank Professor A. Cavaliere for the insightful discussion. (INAF:ASI 2014-049-R.0 - ASI; AST-1615796 - National Science Foundation; 80NSSC17K0309 - NASA Swift Guest Investigator grant; DN 08-1/2016 - Bulgarian National Science Fund of the Ministry of Education and Science; 17-12-01029 - Russian Science Foundation)
Published: 2018

37. The host galaxy of the γ-ray-emitting narrow-line Seyfert 1 galaxy PKS 1502+036

Author: Ranieri D. Baldi, Alessandro Capetti, F. D'Ammando, M. Orienti, C. Ramos Almeida, C. M. Raiteri, J. A. Acosta-Pulido, ITA, and ESP
Subjects: Physics, Luminous infrared galaxy, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Center (category theory), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Luminosity, Astrophysical jet, Space and Planetary Science, Bulge, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Elliptical galaxy, Surface brightness, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The detection of gamma-ray emission from narrow-line Seyfert 1 galaxies (NLSy1) has challenged the idea that large black hole (BH) masses ($\ge$10$^8$ M$_{\odot}$) are needed to launch relativistic jets. We present near-infrared imaging data of the gamma-ray-emitting NLSy1 PKS 1502+036 obtained with the Very Large Telescope. Its surface brightness profile, extending to $\sim$ 20 kpc, is well described by the combination of a nuclear component and a bulge with a Sersic index $n$ = 3.5, which is indicative of an elliptical galaxy. A circumnuclear structure observed near PKS 1502+036 may be the result of galaxy interactions. A BH mass of about $\sim 7 \times 10^{8}$ M$_{\odot}$ has been estimated by the bulge luminosity. The presence of an additional faint disc component cannot be ruled out with the present data, but this would reduce the BH mass estimate by only $\sim$ 30%. These results, together with analogous findings obtained for FBQS J1644+2619, indicate that the relativistic jets in gamma-ray-emitting NLSy1 are likely produced by massive black holes at the center of elliptical galaxies., Comment: 5 pages, 2 figures, 1 table, and 2 supplementary figures. Monthly Notices of the Royal Astronomical Society Letters, Volume 478, Issue 1, L66-L71
Published: 2018

38. THE 2009 DECEMBER GAMMA-RAY FLARE OF 3C 454.3: THE MULTIFREQUENCY CAMPAIGN

Author: L. Salotti, E. Moretti, Mark Gurwell, C. Pittori, M. Tavani, S. Vercellone, V. Vittorini, F. Longo, T. Sakamoto, Martino Marisaldi, A. Morselli, M. Galli, P. Santolamazza, G. Barbiellini P. Caraveo, Elena Pian, C. M. Raiteri, M. Pilia, Francesco Lucarelli, A. Trois, A. Rubini, F. D'Ammando, F. Verrecchia, Michael C. Stroh, M. Prest, F. Perotti, Andrea Tiengo, E. Vallazza, P. W. Cattaneo, M. Feroci, Merja Tornikoski, M. Villata, L. Pacciani, P. Picozza, A. Pellizzoni, E. Costa, E. Del Monte, A. Rappoldi, M. Fiorini, Ryosuke Itoh, P. A. Curran, Masayuki Yamanaka, G. Pucella, F. Lazzarotto, Valeri M. Larionov, C. S. Lin, F. Gianotti, A. C. Sadun, A. Giuliani, V. Cocco, Arnaud Ferrari, P. Lipari, M. Trifoglio, M. Fiocchi, E. Morelli, Andrei Berdyugin, G. Piano, H. A. Krimm, Sandro Mereghetti, L. O. Takalo, A. D. Falcone, S. Colafrancesco, Claudio Labanti, D. Zanello, F. Fuschino, D. Fugazza, G. Di Cocco, M. Rapisarda, A. Argan, Andrea Bulgarelli, Makoto Uemura, P. Giommi, Anne Lähteenmäki, G. De Paris, I. Donnarumma, Y. Evangelista, P. Soffitta, A. W. Chen, Paolo Leto, Hugh D. Aller, E. Striani, Mahito Sasada, I. Lapshov, M. F. Aller, S. Sabatini, Pacciani L, Vittorini V, Tavani M, Fiocchi MT, Vercellone S, DAmmando F, Sakamoto T, Pian E, Raiteri CM, Villata M, Sasada M, Itoh R, Yamanaka M, Uemura M, Striani E, Fugazza D, Tiengo A, Krimm HA, Stroh MC, Falcone AD, Curran PA, Sadun AC, Lahteenmaki A, Tornikoski M, Aller HD, Aller MF, Lin CS, Larionov VM, Leto P, Takalo LO, Berdyugin A, Gurwell MA, Bulgarelli A, Chen AW, Donnarumma I, Giuliani A, Longo F, Pucella G, Argan A, Barbiellini G, Caraveo P, Cattaneo PW, Costa E, De Paris G, Del Monte E, Di Cocco G, Evangelista Y, Ferrari A, Feroci M, Fiorini M, Fuschino F, Galli M, Gianotti F, Labanti C, Lapshov I, Lazzarotto F, Lipari P, Marisaldi M, Mereghetti S, Morelli E, Moretti E, Morselli A, Pellizzoni A, Perotti F, Piano G, Picozza P, Pilia M, Prest M, Rapisarda M, Rappoldi A, Rubini A, Sabatini S, Soffitta P, Trifoglio M, Trois A, Vallazza E, Zanello D, Colafrancesco S, Pittori C, Verrecchia F, Santolamazza P, Lucarelli F, Giommi P, Salotti L, L., Pacciani, V., Vittorini, M., Tavani, M. T., Fiocchi, S., Vercellone, F., D'Ammando, T., Sakamoto, E., Pian, C. M., Raiteri, M., Villata, M., Sasada, R., Itoh, M., Yamanaka, M., Uemura, E., Striani, D., Fugazza, A., Tiengo, H. A., Krimm, M. C., Stroh, A. D., Falcone, P. A., Curran, A. C., Sadun, A., Lahteenmaki, M., Tornikoski, H. D., Aller, M. F., Aller, C. S., Lin, V. M., Larionov, P., Leto, L. O., Takalo, A., Berdyugin, M. A., Gurwell, A., Bulgarelli, A. W., Chen, I., Donnarumma, A., Giuliani, Longo, Francesco, G., Pucella, A., Argan, G., Barbiellini, P., Caraveo, P. W., Cattaneo, E., Costa, G. D., Pari, E. D., Monte, G. D., Cocco, Y., Evangelista, A., Ferrari, M., Feroci, M., Fiorini, F., Fuschino, M., Galli, F., Gianotti, C., Labanti, I., Lapshov, F., Lazzarotto, P., Lipari, M., Marisaldi, S., Mereghetti, E., Morelli, E., Moretti, A., Morselli, A., Pellizzoni, F., Perotti, G., Piano, P., Picozza, M., Pilia, M., Prest, M., Rapisarda, A., Rappoldi, A., Rubini, S., Sabatini, P., Soffitta, M., Trifoglio, A., Troi, E., Vallazza, D., Zanello, S., Colafrancesco, C., Pittori, F., Verrecchia, P., Santolamazza, F., Lucarelli, P., Giommi, and L., Salotti
Subjects: Agile, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, galaxies: active, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, gamma-ray source, High Energy Gamma-ray Astronomy, AGILE satellite, Active Galactic Nuclei, Spectral line, blazar, law.invention, Accretion disc, multi wavelength observation, law, quasars: general, Blazar, media_common, Physics, galaxies: individual (3C 454.3), Gamma ray, Astronomy and Astrophysics, radiation mechanisms: non-thermal, Wavelength, Space and Planetary Science, Sky, Flare
Abstract: During the month of 2009 December, the blazar 3C 454.3 became the brightest gamma-ray source in the sky, reaching a peak flux F 2000 × 10 -8 photons cm-2 s-1 for E > 100 MeV. Starting in 2009 November intensive multifrequency campaigns monitored the 3C 454 gamma-ray outburst. Here, we report on the results of a two-month campaign involving AGILE, INTEGRAL, Swift/XRT, Swift/BAT, and Rossi XTE for the high-energy observations and Swift/UVOT, KANATA, Goddard Robotic Telescope, and REM for the near-IR/optical/UV data. GASP/WEBT provided radio and additional optical data. We detected a long-term active emission phase lasting 1 month at all wavelengths: in the gamma-ray band, peak emission was reached on 2009 December 2-3. Remarkably, this gamma-ray super-flare was not accompanied by correspondingly intense emission in the optical/UV band that reached a level substantially lower than the previous observations in 2007-2008. The lack of strong simultaneous optical brightening during the super-flare and the determination of the broadband spectral evolution severely constrain the theoretical modeling. We find that the pre- and post-flare broadband behavior can be explained by a one-zone model involving synchrotron self-Compton plus external Compton emission from an accretion disk and a broad-line region. However, the spectra of the 2009 December 2-3 super-flare and of the secondary peak emission on 2009 December 9 cannot be satisfactorily modeled by a simple one-zone model. An additional particle component is most likely active during these states. © 2010. The American Astronomical Society. All rights reserved.
Published: 2010
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39. Blazar spectral variability as explained by a twisted inhomogeneous jet

Author: M. S. Butuzova, C. Espinosa, O. Vince, K. Kuratov, Sergey S. Savchenko, Joseph Moody, A. Di Paola, Boyko Mihov, Ivan S. Troitsky, L. V. Larionova, José L. Gómez, T. S. Grishina, Mark Gurwell, Sol N. Molina, Brian Skiff, V. Bozhilov, G. V. Baida, D. A. Morozova, A. A. Mokrushina, Katsura Matsumoto, Sofia O. Kurtanidze, G. A. Borman, A. Strigachev, C. S. Lin, J. Echevarría, S. V. Nazarov, Raul Michel, G. Rodriguez-Coira, Alan P. Marscher, M. I. Carnerero, C. M. Raiteri, Joni Tammi, N. V. Efimova, Omar M. Kurtanidze, F. Pinna, Iain A. Steele, B. Jordan, B. McBreen, Kozo Sadakane, Paul S. Smith, C. Protasio, Manasvita Joshi, J. M. Ohlert, F. J. Redondo-Lorenzo, Clemens Thum, Elena G. Larionova, T. A. Polakis, L. Slavcheva-Mihova, Carolina Casadio, Anne Lähteenmäki, D. N. Okhmat, M. Villata, Helen Jermak, Erika Benítez, E. N. Kopatskaya, Arkady A. Arkharov, N. Rizzi, J. A. Acosta-Pulido, A. A. Vasilyev, Michael P. Malmrose, M. Minev, N. Castro-Segura, M. G. Nikolashvili, P. Calcidese, Manash R. Samal, Sh. A. Ehgamberdiev, Merja Tornikoski, C. Lázaro, Filippo D'Ammando, W. Boschin, T. Pursimo, D. Carosati, Rumen Bachev, A. C. Sadun, Goran Damljanović, Evgeni Semkov, D. O. Mirzaqulov, Evgeni Ovcharov, Yu. V. Troitskaya, Svetlana G. Jorstad, David Hiriart, A. Giunta, Antonio Fuentes, Ivan Agudo, Valeri M. Larionov, and Wen Ping Chen
Subjects: ACTIVE GALACTIC NUCLEI, Brightness, Active galactic nucleus, PARTICLE-ACCELERATION, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Relativistic beaming, Astrophysical jet, 0103 physical sciences, HELICAL JETS, PHOTOMETRY, OUTBURST, Blazar, 010303 astronomy & astrophysics, QC, QB, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Multidisciplinary, ta115, ta114, 010308 nuclear & particles physics, EXTRAGALACTIC RADIO-SOURCES, COMPARISON STARS, Quasar, Astrophysics - Astrophysics of Galaxies, Galaxy, CTA-102, QUASARS, WEBT CAMPAIGN, Astrophysics of Galaxies (astro-ph.GA), RELATIVISTIC JETS, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Blazar emission is dominated by non-thermal radiation from a relativistic jet pointing toward us, therefore undergoing Doppler beaming. This is responsible for flux enhancement and contraction of the variability time scales, so that most blazars appear as luminous sources characterized by noticeable and fast flux changes at all frequencies. The mechanisms producing their unpredictable variability are debated and include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the emitting knots or jet regions have also been suggested to explain flaring events or specific properties such as intraday variability, quasi-periodicities, or the delay of radio flux variations relative to optical changes. However, such a geometric interpretation has not been universally accepted because alternative explanations based on changes of physical conditions can also work in many cases. Here we report the results of optical-to-radio monitoring of the blazar CTA 102 by the Whole Earth Blazar Telescope Collaboration and show that the observed long-term flux and spectral variability is best explained by an inhomogeneous, curved jet that undergoes orientation changes. We propose that magnetohydrodynamic instabilities or rotation of a twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the recent extreme optical outburst (six magnitudes) occurred when the corresponding jet emitting region acquired a minimum viewing angle., Comment: 31 pages, 11 figures. This is the accepted version (before Nature editing) of the paper published by Nature, online version at http://dx.doi.org/10.1038/nature24623, Nature 2017/12/04/online
Published: 2017

40. Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability

Author: Boyko Mihov, R. Zanmar Sanchez, Goran Damljanović, Evgeni Semkov, D. O. Mirzaqulov, Ivan S. Troitsky, Sergey S. Savchenko, Georgia Panopoulou, F. Pinna, L. Slavcheva-Mihova, J. M. Ohlert, N. Rizzi, Fabrizio Nicastro, J. A. Acosta-Pulido, A. Pastor Yabar, Daria A. Morozova, C. Lázaro, Giuseppe Leto, R. Bachev, M. I. Carnerero, Sh. A. Ehgamberdiev, Merja Tornikoski, S. V. Nazarov, M. Cecconi, T. S. Grishina, Dmitry A. Blinov, O. Vince, A. A. Mokrushina, P. C. Huang, Ioannis Liodakis, A. Di Paola, A. A. Vasilyev, Sofia O. Kurtanidze, L. V. Larionova, Arkady A. Arkharov, G. A. Borman, Marcello Giroletti, C. M. Raiteri, A. Strigachev, S. A. Klimanov, P. A. González-Morales, C. Martínez-Lombilla, A. B. Grinon-Marin, R. J. C. Vera, Antonio Stamerra, Joseph Moody, C. Protasio, M. Villata, M. J. Arévalo, Anne Lähteenmäki, Yu. V. Troitskaya, M. G. Nikolashvili, Evgenia N. Kopatskaya, Lorand A. Sigua, O. M. Kurtanidze, Valeri M. Larionov, Wen Ping Chen, D. Carosati, A. C. Sadun, Antonio Frasca, Sunay Ibryamov, Elena G. Larionova, INAF - Osservatorio Astrofisico di Torino, INAF - Osservatorio Astronomico di Roma, Scuola Normale Superiore di Pisa, St. Petersburg State University, Instituto de Astrofísica de Canarias, RAS - Pulkovo Astronomical Observatory, Bulgarian Academy of Sciences, Crimean Astrophysical Observatory, EPT Observatories, TNG Fundación Galileo Galilei, National Central University, Astronomical Observatory, Osservatorio Astronomico Roma, Academy of Sciences of the Republic of Uzbekistan, Osservatorio Astrofisico di Catania, INAF Istituto di Radioastronomia, Georgian National Academy of Sciences, Department of Radio Science and Engineering, University of Crete, Brigham Young University, Münster University of Applied Sciences, Osservatorio Astronomico Sirio, University of Colorado Denver, Metsähovi Radio Observatory, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University
Subjects: Swift Gamma-Ray Burst Mission, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Polarimetry, FOS: Physical sciences, Astrophysics, BL Lacertae objects: individual: PG 1553+113, 01 natural sciences, law.invention, Telescope, law, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, individual: PG 1553+113 [BL Lacertae objects], Physics, High Energy Astrophysical Phenomena (astro-ph.HE), ta115, 010308 nuclear & particles physics, general [BL Lacertae objects], Astronomy, Astronomy and Astrophysics, BL Lacertae objects: general, Galaxies: active, Polarization (waves), Light curve, Astrophysics - Astrophysics of Galaxies, Synchrotron, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena, BL Lac object
Abstract: In 2015 July 29 - September 1 the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 hours. During one of these epochs, simultaneous observations by the Swift satellite were requested to compare the results of the X-ray and optical-UV instruments. Optical, near-infrared and radio monitoring was carried out by the Whole Earth Blazar Telescope (WEBT) collaboration for the whole observing season. We here present the results of the analysis of all these data, together with an investigation of the source photometric and polarimetric behaviour over the last three years. The 2015 EPIC spectra show slight curvature and the corresponding light curves display fast X-ray variability with a time scale of the order of 1 hour. In contrast to previous results, during the brightest X-ray states detected in 2015 the simple log-parabolic model that best-fits the XMM-Newton data also reproduces reasonably well the whole synchrotron bump, suggesting a peak in the near-UV band. We found evidence of a wide rotation of the polarization angle in 2014, when the polarization degree was variable, but the flux remained almost constant. This is difficult to interpret with deterministic jet emission models, while it can be easily reproduced by assuming some turbulence of the magnetic field., Comment: 15 pages, 12 figures, accepted by Monthly Notices of the Royal Astronomical Society
Published: 2017

41. A Panchromatic View of Relativistic Jets in Narrow-Line Seyfert 1 Galaxies

Author: Monica Orienti, Filippo D'Ammando, Justin D. Finke, Marcello Giroletti, Josefin Larsson, C. M. Raiteri, Dammando, F, Orienti, M, Finke, J, Larsson, J, Giroletti, M, Raiteri, Cm, DIPARTIMENTO DI FISICA E ASTRONOMIA 'AUGUSTO RIGHI', and Da definire
Subjects: Radio galaxy, galaxies: jet, lcsh:Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Peculiar galaxy, lcsh:QB1-991, Relativistic beaming, Astrophysical jet, 0103 physical sciences, Disc, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Luminous infrared galaxy, Physics, Spiral galaxy, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Quasar, galaxies: nuclei, galaxies: jets, galaxies: Seyfert, gamma-rays: general, Galaxy, astronomy_astrophysics, Black hole, Elliptical galaxy, Astrophysics - High Energy Astrophysical Phenomena, Fermi Gamma-ray Space Telescope
Abstract: The discovery by the Large Area Telescope on board Fermi of variable gamma-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies revealed the presence of a possible third class of Active Galactic Nuclei (AGN) with relativistic jets in addition to blazars and radio galaxies. Considering that NLSy1 are usually hosted in spiral galaxies, this finding poses intriguing questions about the nature of these objects and the formation of relativistic jets. We report on a systematic investigation of the gamma-ray properties of a sample of radio-loud NLSy1, including the detection of new objects, using 7 years of Fermi-LAT data with the new Pass 8 event-level analysis. In addition we discuss the radio-to-very-high-energy properties of the gamma-ray emitting NLSy1, their host galaxy, and black hole mass in the context of the blazar scenario and the unification of relativistic jets at different scales., 11 pages, 2 figures. Accepted for publication in the special issue of Galaxies, "Blazars through Sharp Multi-wavelength Eyes", edited by J. L. Gomez, A. P. Marscher, and S. G. Jorstad. arXiv admin note: text overlap with arXiv:1503.01480
Published: 2016

42. Investigating the peculiar emission from the new VHE gamma-ray source H1722+119

Author: M. Hayashida, M. Makariev, B. Biasuzzi, K. Mallot, R. J. García López, Louis Antonelli, D. Dominis Prester, E. Prandini, M. Doert, M. H. Wu, Massimo Persic, F. D'Ammando, Marc Ribó, G. Bonnoli, Abelardo Moralejo, Juri Poutanen, R. Reinthal, V. Fallah Ramazani, P. Bangale, Y. Hanabata, Razmik Mirzoyan, U. Barres de Almeida, Damir Lelas, T. Steinbring, Marina Manganaro, P. G. Prada Moroni, Stefano Covino, Hidetoshi Kubo, P. Antoranz, D. Galindo, J. Becerra González, G. Pedaletti, Dorota Sobczyńska, D. Nakajima, Thomas Bretz, J. Hose, Andrei Berdyugin, Pratik Majumdar, M. V. Fonseca, S. Bonnefoy, A. Sillanpää, Arka Chatterjee, Francesco Longo, D. Elsaesser, F. Di Pierro, K. Kodani, Alexander Hahn, Konstancja Satalecka, Walter Max-Moerbeck, Tomoki Saito, D. Tescaro, Ivica Puljak, Pierre Colin, H. Takami, L. Nogués, U. Menzel, Michele Doro, M. I. Martínez, Gareth Hughes, Talvikki Hovatta, C. Schultz, E. Moretti, Marcel Strzys, D. Fidalgo, Vassil Verguilov, Aaron Dominguez, Diego F. Torres, Julia Thaele, E. de Oña Wilhelmi, Reiko Orito, F. Verrecchia, Sabrina Einecke, Junko Kushida, P. Da Vela, R. López-Coto, J. Rodriguez Garcia, J. E. Ward, M. Palatiello, Elina Lindfors, A. Niedzwiecki, Kyoshi Nishijima, Ievgen Vovk, Wolfgang Rhode, Daniel Mazin, Oscar Blanch, Julian Sitarek, Juan Abel Barrio, L. Maraschi, Francesco Dazzi, David Paneque, A. Fernández-Barral, Markus Garczarczyk, Yusuke Konno, C. Fruck, B. De Lotto, M. Villata, T. Schweizer, T. Toyama, D. Guberman, Tomislav Terzić, K. Frantzen, J. L. Richards, Mosè Mariotti, A.-K. Overkemping, S. Paiano, Saverio Lombardi, Karl Mannheim, D. Hadasch, L. Perri, A. La Barbera, D. Eisenacher Glawion, X. Paredes-Fortuny, P. Temnikov, M. Nievas Rosillo, W. Idec, A. González Muñoz, E. Colombo, B. Banerjee, S. Buson, L. O. Takalo, Masahiro Teshima, Daniela Dorner, R. Zanin, Dariusz Gora, Adrian Biland, M. Gaug, J. Rico, J. Herrera, Koji Noda, Elisa Bernardini, A. De Angelis, A. Treves, Vitaly Neustroev, Jose Luis Contreras, Juan Cortina, G. Maneva, C. M. Raiteri, Nikola Godinovic, Benito Marcote, Max Ludwig Ahnen, Kari Nilsson, P. Giammaria, M. Will, Dario Hrupec, M. A. Lopez, R. Clavero, D. Garrido Terrats, W. Bednarek, Fabrizio Tavecchio, Ll. Font, I. Snidaric, Ana Babić, Stefano Ansoldi, Riccardo Paoletti, J. Palacio, J. M. Paredes, Antonio Stamerra, Alessandro Carosi, Jose Miguel Miranda, F. Borracci, Anthony C. S. Readhead, Universitat de Barcelona, Aalto-yliopisto, Aalto University, Ahnen ML, Ansoldi S, Antonelli LA, Antoranz P, Babic A, Banerjee B, Bangale P, de Almeida UB, Barrio JA, Gonzalez JB, Bednarek W, Bernardini E, Biasuzzi B, Biland A, Blanch O, Bonnefoy S, Bonnoli G, Borracci F, Bretz T, Buson S, Carosi A, Chatterjee A, Clavero R, Colin P, Colombo E, Contreras JL, Cortina J, Covino S, Da Vela P, Dazzi F, De Angelis A, De Lotto B, Wilhelmi ED, Di Pierro F, Doert M, Dominguez A, Prester DD, Dorner D, Doro M, Einecke S, Glawion DE, Elsaesser D, Ramazani VF, Fernandez-Barral A, Fidalgo D, Fonseca MV, Font L, Frantzen K, Fruck C, Galindo D, Lopez RJG, Garczarczyk M, Terrats DG, Gaug M, Giammaria P, Godinovic N, Munoz AG, Gora D, Guberman D, Hadasch D, Hahn A, Hanabata Y, Hayashida M, Herrera J, Hose J, Hrupec D, Hughes G, Idec W, Kodani K, Konno Y, Kubo H, Kushida J, La Barbera A, Lelas D, Lindfors E, Lombardi S, Longo F, Lopez M, Lopez-Coto R, Majumdar P, Makariev M, Mallot K, Maneva G, Manganaro M, Mannheim K, Maraschi L, Marcote B, Mariotti M, Martinez M, Mazin D, Menzel U, Miranda JM, Mirzoyan R, Moralejo A, Moretti E, Nakajima D, Neustroev V, Niedzwiecki A, Rosillo MN, Nilsson K, Nishijima K, Noda K, Nogues L, Orito R, Overkemping A, Paiano S, Palacio J, Palatiello M, Paneque D, Paoletti R, Paredes JM, Paredes-Fortuny X, Pedaletti G, Perri L, Persic M, Poutanen J, Moroni PGP, Prandini E, Puljak I, Rhode W, Ribo M, Rico J, Garcia JR, Saito T, Satalecka K, Schultz C, Schweizer T, Sillanpaa A, Sitarek J, Snidaric I, Sobczynska D, Stamerra A, Steinbring T, Strzys M, Takalo L, Takami H, Tavecchio F, Temnikov P, Terzic T, Tescaro D, Teshima M, Thaele J, Torres DF, Toyama T, Treves A, Verguilov V, Vovk I, Ward JE, Will M, Wu MH, Zanin R, DAmmando F, Berdyugin A, Hovatta T, Max-Moerbeck W, Raiteri CM, Readhead ACS, Reinthal R, Richards JL, Verrecchia F, Villata M, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De Oña Wilhelmi, E., Di Pierro, F., Doert, M., Domínguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Fallah Ramazani, V., Fernández Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., García López, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinović, N., González Muñoz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, López, M., López Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Nogués, L., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schultz, C., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T, Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., D'Ammando, F., Berdyugin, A., Hovatta, T., Max Moerbeck, W., Raiteri, C. M., Readhead, A. C. S., Reinthal, R., Richards, J. L., Verrecchia, F., and Villata, M.
Subjects: galaxie [Gamma-rays], gamma-rays: galaxies, UPGRADE, Astrophysics, DETECTED BLAZARS, 01 natural sciences, LARGE-AREA TELESCOPE, law.invention, Raigs gamma, law, galaxies: active, BL Lacertae objects: individual: H1722+119, galaxies, distances and redshifts, BL LACERTAE OBJECTS, ALL-SKY SURVEY, MAGIC, TELESCOPES, LAC OBJECTS, SOURCE CATALOG, MAJOR, HELICAL JETS, CRAB-NEBULA, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), distances and redshift [Galaxies], active BL Lacertae objects, individual, H1722+119 galaxies, distances and redshifts gamma-rays, Galaxies: active, Galaxies: distances and redshifts, Gamma-rays: galaxies, Astronomy and Astrophysics, Space and Planetary Science, galaxies [Gamma-rays], Extragalactic background light, Spectral energy distribution, Electrónica, Física nuclear, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Owens Valley Radio Observatory, Astrophysics::Cosmology and Extragalactic Astrophysics, Telescope, galaxies: active, BL Lacertae objects: individual: H1722+119, galaxies: distances and redshifts, gamma-rays: galaxies, 0103 physical sciences, individual: H1722+119 [BL Lacertae objects], distances and redshifts [Galaxies], ta115, 010308 nuclear & particles physics, Gamma rays, Astronomy, Astronomy and Astrophysic, Redshift, Crab Nebula, 13. Climate action, Galàxies actives, Active galaxies, ddc:520
Abstract: The MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes observed the BL Lac object H1722+119 (redshift unknown) for six consecutive nights between 2013 May 17 and 22, for a total of 12.5 h. The observations were triggered by high activity in the optical band measured by the KVA (Kungliga Vetenskapsakademien) telescope. The source was for the first time detected in the very high energy (VHE, $E > 100$ GeV) $\gamma$-ray band with a statistical significance of 5.9 $\sigma$. The integral flux above 150 GeV is estimated to be $(2.0\pm 0.5)$ per cent of the Crab Nebula flux. We used contemporaneous high energy (HE, 100 MeV $ < E < 100$ GeV) $\gamma$-ray observations from Fermi-LAT (Large Area Telescope) to estimate the redshift of the source. Within the framework of the current extragalactic background light models, we estimate the redshift to be $z = 0.34 \pm 0.15$. Additionally, we used contemporaneous X-ray to radio data collected by the instruments on board the Swift satellite, the KVA, and the OVRO (Owens Valley Radio Observatory) telescope to study multifrequency characteristics of the source. We found no significant temporal variability of the flux in the HE and VHE bands. The flux in the optical and radio wavebands, on the other hand, did vary with different patterns. The spectral energy distribution (SED) of H1722+119 shows surprising behaviour in the $\sim 3\times10^{14} - 10^{18}$ Hz frequency range. It can be modelled using an inhomogeneous helical jet synchrotron self-Compton model., Comment: 12 pages, 5 figures, 2 tables
Published: 2016
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43. 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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44. 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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45. Flare activity of the blazar 3C454.3 from gamma to radio wavelengths in 2004-2010

Author: S. A. Klimanov, V. T. Doroshenko, S. G. Sergeev, V. I. Zhdanov, Hugh D. Aller, Y. Efimov, I. B. Vavilova, Alexander B. Pushkarev, N. G. Chesnok, Joni Tammi, M. F. Aller, Merja Tornikoski, P. Savolainen, L. N. Volvach, C. M. Raiteri, S. V. Nazarov, E. Fedorova, A. E. Volvach, A. M. Kutkin, M. G. Larionov, Anne Lähteenmäki, M. Villata, and G. V. Borman
Subjects: Physics, Wavelength, law, Astronomy, Blazar, Flare, law.invention
Published: 2011
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46. 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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47. 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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48. Radio-to-UV monitoring of AO 0235+164 by the WEBT and Swift during the 2006–2007 outburst

Author: C. M. Raiteri, M. Villata, V. M. Larionov, M. F. Aller, U. Bach, M. Gurwell, O. M. Kurtanidze, A. Lähteenmäki, K. Nilsson, A. Volvach, H. D. Aller, A. A. Arkharov, R. Bachev, A. Berdyugin, M. Böttcher, C. S. Buemi, P. Calcidese, E. Cozzi, A. Di Paola, M. Dolci, J. H. Fan, E. Forné, L. Foschini, A. C. Gupta, V. A. Hagen-Thorn, L. Hooks, T. Hovatta, M. Joshi, M. Kadler, G. N. Kimeridze, T. S. Konstantinova, A. Kostov, T. P. Krichbaum, L. Lanteri, L. V. Larionova, C.-U. Lee, P. Leto, E. Lindfors, F. Montagni, R. Nesci, E. Nieppola, M. G. Nikolashvili, J. Ohlert, A. Oksanen, E. Ovcharov, P. Pääkkönen, M. Pasanen, T. Pursimo, J. A. Ros, E. Semkov, L. A. Sigua, R. L. Smart, A. Strigachev, L. O. Takalo, K. Torii, I. Torniainen, M. Tornikoski, C. Trigilio, H. Tsunemi, G. Umana, and A. Valcheva
Subjects: Physics, Time delays, Brightness, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Phase (waves), FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics, Light curve, Synchrotron, law.invention, Wavelength, Space and Planetary Science, law, Blazar
Abstract: The blazar AO 0235+164 was claimed to show a quasi-periodic behaviour in the radio and optical bands. Moreover, an extra emission component contributing to the UV and soft X-ray flux was detected, whose nature is not yet clear. A predicted optical outburst was observed in late 2006/early 2007. We here present the radio-to-optical WEBT light curves during the outburst, together with UV data acquired by Swift in the same period. We found the optical outburst to be as strong as the big outbursts of the past: starting from late September 2006, a brightness increase of 5 mag led to the outburst peak in February 19-21, 2007. We also observed an outburst at mm and then at cm wavelengths, with an increasing time delay going toward lower frequencies during the rising phase. Cross-correlation analysis indicates that the 1 mm and 37 GHz flux variations lagged behind the R-band ones by about 3 weeks and 2 months, respectively. These short time delays suggest that the corresponding jet emitting regions are only slightly separated and/or misaligned. In contrast, during the outburst decreasing phase the flux faded contemporaneously at all cm wavelengths. This abrupt change in the emission behaviour may suggest the presence of some shutdown mechanism of intrinsic or geometric nature. The behaviour of the UV flux closely follows the optical and near-IR one. By separating the synchrotron and extra component contributions to the UV flux, we found that they correlate, which suggests that the two emissions have a common origin., Comment: 9 pages, 7 figures, in press for Astronomy and Astrophysics
Published: 2008
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49. Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

Author: K. Nishijima, J. L. Richards, Stefano Covino, G. Piner, D. Dominis Prester, U. Menzel, A. Flinders, D. Tescaro, Louis Antonelli, D. Galindo, Aaron Dominguez, S. Schröder, Elena G. Larionova, Kari Nilsson, Paul S. Smith, A. McCann, T. S. Grishina, Wen Ping Chen, M. Will, Pratik Majumdar, J. E. Ward, Daniela Dorner, Dariusz Gora, P. Moriarty, C. Rulten, Soebur Razzaque, D. Garrido Terrats, K. Frantzen, Joseph Moody, Wystan Benbow, G. Hughes, K. Ragan, Ralph Bird, L. Perri, M. Gaug, T. Sakamoto, Valeri M. Larionov, Elina Lindfors, G. H. Sembroski, Daniel Mazin, Ievgen Vovk, A. Hahn, M. Hütten, N. H. Park, Alexander B. Pushkarev, G. Maccaferri, Thomas Bretz, P. Wilcox, P. Kar, D. Nakajima, R. Zanin, J. Herrera, Wei Cui, Amanda Weinstein, J. Palacio, P. G. Prada Moroni, Frank Krennrich, Matthew L. Lister, A. Berti, A. Cesarini, M. Kertzman, A. La Barbera, Walter Max-Moerbeck, E. Colombo, M. Villata, M. P. Connolly, Adrian Biland, D. S. Hanna, Ana Babić, D. Eisenacher Glawion, Juan Abel Barrio, John L. Quinn, M. Capalbi, Koji Noda, Arka Chatterjee, Elisa Bernardini, A. Sillanpää, Adrian Rovero, Antonio Stamerra, J. V. Tucci, M. Nievas Rosillo, M. Palatiello, L. V. Larionova, S. N. Shore, R. Mukherjee, M. J. Lang, Daniel Nieto, M. I. Martínez, S. Bonnefoy, J. Kushida, P. Giammaria, P. Bangale, Wolfgang Rhode, Gernot Maier, G. Pedaletti, L. O. Takalo, Margo F. Aller, Jose Luis Contreras, Andrei Berdyugin, J. A. Zensus, E. Roache, V. Verguilov, D. Fidalgo, C. Pace, Thomas P. Krichbaum, Francesco Dazzi, Juan Cortina, M. Engelkemeier, G. H. Gillanders, A. Carraminyana, S. P. Wakely, Mosè Mariotti, J. Rico, A. Fernández-Barral, R. Clavero, J. Becerra González, A.-K. Overkemping, S. O. Kurtanidze, Sabrina Einecke, Abraham D. Falcone, A. González Muñoz, Evgenia N. Kopatskaya, Lars Fuhrmann, Nikola Godinovic, Benito Marcote, Karlen Shahinyan, Takashi Saito, W. Bednarek, C. Schultz, Marcos Santander, Fabrizio Tavecchio, J. Rodriguez Garcia, E. Pueschel, Ll. Font, A. C. Sadun, A. Popkow, J. Grube, V. Bugaev, Anthony C. S. Readhead, R. Ligustri, A. Archer, I. Snidaric, Yusuke Konno, P. Calcidese, M. Strzys, A. Pichel, Saverio Lombardi, B. De Lotto, Markus Garczarczyk, N. Kelley-Hoskins, J. Tyler, Ann E. Wehrle, B. Banerjee, S. Buson, D. Hadasch, N. Otte, Maria G. Nikolashvili, Gordon T. Richards, L. Nogués, B. Biasuzzi, Juri Poutanen, U. Barres de Almeida, J. P. Finley, K. Mallot, S. Paiano, Marcello Giroletti, I. Nestoras, A. De Angelis, A. Treves, Vitaly Neustroev, X. Paredes-Fortuny, T. B. Humensky, R. A. Ong, Karl Mannheim, J. H. Buckley, Yu. A. Kovalev, R. J. García López, H. Fleischhack, G. N. Kimeridze, I. Sadeh, David A. Williams, Y. Mori, M. V. Fonseca, W. Idec, Matthias Kadler, Yuri Y. Kovalev, Stefano Ansoldi, Riccardo Paoletti, K. Kodani, J. P. Norris, O. M. Kurtanidze, N. V. Efimova, Y. Hanabata, Arkady A. Arkharov, Anne Lähteenmäki, Abelardo Moralejo, G. Maneva, Masahiro Teshima, A. C. Zook, Dario Hrupec, P. Antoranz, B. Zitzer, Hugh Dickinson, R. A. Chigladze, M. Peresano, Ekaterina Koptelova, S. Archambault, M. A. Lopez, T. Steinbring, P. Temnikov, P. Leto, Massimo Persic, J. M. Paredes, Hugh D. Aller, F. Borracci, S. O'Brien, T. Surić, I. Telezhinsky, I. Reichardt, Jamie Holder, G. Vanzo, R. Pearson, Julia Thaele, G. Bonnoli, Mark Gurwell, Eduardo Ros, Andrea Orlati, S. Griffin, L. A. Sigua, Diego F. Torres, Alessandro Carosi, Ruben Lopez-Coto, Maria Krause, Y. Yatsu, A. Wilhelm, Jose Miguel Miranda, Anushka Udara Abeysekara, T. Schweizer, P. Cassaro, Razmik Mirzoyan, E. Moretti, Damir Lelas, Francesco Longo, V. Fallah Ramazani, P. Kaaret, Dorota Sobczyńska, L. Maraschi, Kirill Sokolovsky, Tomislav Terzić, Lucy Fortson, E. de Ona Wilhelmi, Julian Sitarek, C. Fruck, T. Toyama, Ivica Puljak, Max Ludwig Ahnen, David Kieda, F. Di Pierro, Pierre Colin, M. Buchovecky, Oscar Blanch, P. Da Vela, A. Niedzwiecki, Emmanouil Angelakis, M. Doert, M. H. Wu, Ivan S. Troitsky, C. Pagani, David Paneque, Q. Feng, Vladimir A. Hagen-Thorn, E. De la Fuente, E. Prandini, C. M. Raiteri, L. Carrasco, D. Guberman, Jeremy S. Perkins, Martin Pohl, Marina Manganaro, H. A. Krimm, Merja Tornikoski, Konstancja Satalecka, Michele Doro, Dmitry A. Blinov, M. Perri, J. Hose, D. Elsaesser, Daria A. Morozova, P. T. Reynolds, M. Hayashida, Marc Ribó, Hidetoshi Kubo, M. Makariev, Swiss Federal Institute of Technology Zurich, University of Udine, INAF National Institute for Astrophysics, University of Siena, University of Rijeka, Saha Institute of Nuclear Physics, Max Planck Institute for Physics, Complutense University, University of La Laguna, University of Łódź, German Electron Synchrotron, Autonomous University of Barcelona, University of Würzburg, University of Padova, Institute of Space Studies of Catalonia, Dortmund University, Finnish MAGIC Consortium, University of Barcelona, The University of Tokyo, Bulgarian Academy of Sciences, Osservatorio Astronomicodi Roma, University of Pisa, ICREA, University of Maryland, College Park, McGill University, Washington University St. Louis, Harvard University, University College Dublin, University of California Los Angeles, National University of Ireland, Galway, Purdue University, Iowa State University, Pennsylvania State University, University of Utah, University of Minnesota Twin Cities, Adler Planetarium and Astronomy Museum, University of Delaware, Columbia University, University of Iowa, DePauw University, Georgia Institute of Technology, University of Chicago, NASA Goddard Space Flight Center, Universidad de Buenos Aires, Cork Institute of Technology, University of California Santa Cruz, Argonne National Laboratory, University of Johannesburg, University of Michigan, Ann Arbor, St. Petersburg State University, RAS - Pulkovo Astronomical Observatory, Circolo Astrofili Talmassons, Osservatorio Astrofisico della Regione Autonoma Valle d'Aosta, Georgian National Academy of Sciences, National Central University, Aoyama Gakuin University, University of Colorado Denver, Brigham Young University, Tokyo Institute of Technology, Instituto Nacional de Astrofisica Optica y Electronica, Universidad de Guadalajara, University of Denver, University of Arizona, Space Science Institute, Pomona College, University of Leicester, ASI Science Data Center, University of Trento, RAS - P.N. Lebedev Physics Institute, Max Planck Institute for Radio Astronomy, Whittier College, Metsähovi Radio Observatory, INAF Istituto di Radioastronomia, Osservatorio Astrofisico di Catania, California Institute of Technology, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra GonzÃ¡lez, J., Bednarek, W., Bernardini, E., Berti, Alessio, Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Buson, S., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., De OÃ±a Wilhelmi, E., Di Pierro, F., Doert, M., Domãnguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Eisenacher Glawion, D., Elsaesser, D., Engelkemeier, M., Fallah Ramazani, V., FernÃ¡ndez Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., GarcÃa LÃ³pez, R. J., Garczarczyk, M., Garrido Terrats, D., Gaug, M., Giammaria, P., Godinoviä , N., GonzÃ¡lez MuÃ±oz, A., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lã³pez, M., LÃ³pez Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martãnez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nilsson, K., Nishijima, K., Noda, K., Noguã©s, L., Overkemping, A., Paiano, S., Palacio, J., Palatiello, Michele, Paneque, D., Paoletti, R., Paredes, J. M., Paredes Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Poutanen, J., Prada Moroni, P. G., Prandini, E., Puljak, I., Reichardt, I., Rhode, W., Ribã³, M., Rico, J., Rodriguez Garcia, J., Saito, T., Satalecka, K., Schrã¶der, S., Schultz, C., Schweizer, T., Shore, S. N., Sillanpã¤ã¤, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Suriä , T., Takalo, L., Tavecchio, F., Temnikov, P., Terziä , T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vanzo, G., Verguilov, V., Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Abeysekara, A. U., Archambault, S., Archer, A., Benbow, W., Bird, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Connolly, M. P., Cui, W., Dickinson, H. J., Falcone, A., Feng, Q., Finley, J. P., Fleischhack, H., Flinders, A., Fortson, L., Gillanders, G. H., Griffin, S., Grube, J., Hã¼tten, M., Hanna, D., Holder, J., Humensky, T. B., Kaaret, P., Kar, P., Kelley Hoskins, N., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Lang, M. J., Maier, G., Mccann, A., Moriarty, P., Mukherjee, R., Nieto, D., O'Brien, S., Ong, R. A., Otte, N., Park, N., Perkins, J., Pichel, A., Pohl, M., Popkow, A., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Telezhinsky, I., Tucci, J. V., Tyler, J., Wakely, S. P., Weinstein, A., Wilcox, P., Wilhelm, A., Williams, D. A., Zitzer, B., Razzaque, S., Villata, M., Raiteri, C. M., Aller, H. D., Aller, M. F., Larionov, V. M., Arkharov, A. A., Blinov, D. A., Efimova, N. V., Grishina, T. S., Hagen Thorn, V. A., Kopatskaya, E. N., Larionova, L. V., Larionova, E. G., Morozova, D. A., Troitsky, I. S., Ligustri, R., Calcidese, P., Berdyugin, A., Kurtanidze, O. M., Nikolashvili, M. G., Kimeridze, G. N., Sigua, L. A., Kurtanidze, S. O., Chigladze, R. A., Chen, W. P., Koptelova, E., Sakamoto, T., Sadun, A. C., Moody, J. W., Pace, C., Pearson, R., Yatsu, Y., Mori, Y., Carraminyana, A., Carrasco, L., De La Fuente, E., Norris, J. P., Smith, P. S., Wehrle, A., Gurwell, M. A., Zook, A., Pagani, C., Perri, M., Capalbi, M., Cesarini, A., Krimm, H. A., Kovalev, Y. Y., Kovalev, Y. u. A., Ros, E., Pushkarev, A. B., Lister, M. L., Sokolovsky, K. V., Kadler, M., Piner, G., Lã¤hteenmã¤ki, A., Tornikoski, M., Angelakis, E., Krichbaum, T. P., Nestoras, I., Fuhrmann, L., Zensus, J. A., Cassaro, P., Orlati, A., Maccaferri, G., Leto, P., Giroletti, M., Richards, J. L., Max Moerbeck, W., and Readhead, A. C. S.
Subjects: extragalactic background light, multiwavelength observations, Astrophysics::High Energy Astrophysical Phenomena, bl-lacertae objects, Galaxies: BL Lacertae objects: individual: Markarian 501, Methods: data analysis, observational, Polarization, spectral energy-distribution, Flux, FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, individual: Markarian 501 [BL Lacertae objects], law, Coincident, 0103 physical sciences, ddc:530, MAGIC (telescope), crab-nebula, Blazar, data analysis [Methods], 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), tev blazars, 010308 nuclear & particles physics, stochastic acceleration, telescope observations, Institut für Physik und Astronomie, Astronomy and Astrophysics, Astronomy and Astrophysic, gamma-ray emission, methods: data analysis, BL Lacertae objects: individual: Markarian 501, Synchrotron, data analysi [Methods], Space and Planetary Science, x-ray, ddc:520, Electrónica, Física nuclear, Electricidad, Degeneracy (mathematics), Astrophysics - High Energy Astrophysical Phenomena, Flare, BL Lac object
Abstract: Astronomy and astrophysics 603, A31 (2017). doi:10.1051/0004-6361/201629540, We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the γ-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV tohard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the γ-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Aims. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the “single-curve SSC model adjustment” typically reported in the literature. Methods. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very-high-energy (>100 GeV, VHE) γ rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE γ rays). Results. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE γ rays do not make a dominant contribution to the ~1 keV emission. Alternatively, there could be a very variable component contributing to the VHE γ-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed γ-ray flaring activity, with the EVPA rotation coincident with the first γ-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties., Published by EDP Sciences, Les Ulis
Published: 2016
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50. Testing the blazar sequence with the least luminous BL Lacertae objects

Author: Alessandro Capetti, C. M. Raiteri, and ITA
Subjects: Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Spectral density, Flux, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Energy interval, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: In a previous paper, we proposed a new method to select low-power BL Lacs (LPBLs) based on mid-infrared emission and flux contrast through the Ca II spectral break; that study led to the selection of a complete sample formed by 34 LPBLs with 0.05 r = 39.2-41.5 [erg s-1]. We now assemble the broadband spectral energy distributions (SEDs) of these sources to investigate their nature and compare them with brighter BL Lacs. We find that the ratios between the X-ray and radio luminosities range from ~20 to ~30 000 and that the synchrotron peak frequencies span a wide energy interval, from log νpeak ~ 13.5 to ~20 [Hz]. This indicates a broad variety of SED shapes and a mixture of BL Lac flavors. Indeed, although the majority of our LPBLs are high-energy peaked BL Lacs (HBLs), we find that a quarter of them are low-energy peaked BL Lacs (LBLs), despite the fact that the sample is biased against the selection of LBLs. The analysis of the median LPBL SED confirms disagreement with the blazar sequence at low radio luminosities. Furthermore, if we limit the sample to the LBLs subsample, we find that their median SED shape is essentially indistinguishable from that of the most luminous BL Lacs. We conclude that the observed radio power is not the main driving parameter of the multiwavelength properties of BL Lacs.
Published: 2016

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