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Your search keyword '"Saha, L."' showing total 23 results
Start Over Author "Saha, L." Publisher edp sciences
23 results on '"Saha, L."'

1. Study of the GeV to TeV morphology of the γ Cygni SNR (G 78.2+2.1) with MAGIC and Fermi-LAT - Evidence for cosmic ray escape

Author

Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, 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., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., García López, R. J., Garczarczyk, Markus, Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., 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, M., López-Coto, R., López-Oramas, A., Loporchio, S., Machado de Oliveira Fraga, B., Masuda, S., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., 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., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, 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., 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., Torres-Albà, N., Tosti, L., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zarić, D., authors, External, Celli, S., Morlino, G., and MAGIC Collaboration

Subjects
lifetime, model [emission], turbulence, diffusion, energy spectrum, acceleration: shock waves, imaging, GeV, MAGIC, GLAST, emission: model, energy dependence, inverse scattering method, Cherenkov counter, gamma ray, cosmic radiation: galaxy, supernova, ddc:520, galaxy [cosmic radiation], time dependence, TeV, shock waves [acceleration]
Abstract

Astronomy and astrophysics 670, A8 (2023). doi:10.1051/0004-6361/202038748, Context. Diffusive shock acceleration (DSA) is the most promising mechanism that accelerates Galactic cosmic rays (CRs) in the shocks of supernova remnants (SNRs). It is based on particles scattering caused by turbulence ahead and behind the shock. The turbulence upstream is supposedly generated by the CRs, but this process is not well understood. The dominant mechanism may depend on the evolutionary state of the shock and can be studied via the CRs escaping upstream into the interstellar medium (ISM).Aims. Previous observations of the γ Cygni SNR showed a difference in morphology between GeV and TeV energies. Since this SNR has the right age and is at the evolutionary stage for a significant fraction of CRs to escape, our aim is to understand γ-ray emission in the vicinity of the γ Cygni SNR.Methods. We observed the region of the γ Cygni SNR with the MAGIC Imaging Atmospheric Cherenkov telescopes between 2015 May and 2017 September recording 87 h of good-quality data. Additionally, we analysed Fermi-LAT data to study the energy dependence of the morphology as well as the energy spectrum in the GeV to TeV range. The energy spectra and morphology were compared against theoretical predictions, which include a detailed derivation of the CR escape process and their γ-ray generation.Results. The MAGIC and Fermi-LAT data allowed us to identify three emission regions that can be associated with the SNR and that dominate at different energies. Our hadronic emission model accounts well for the morphology and energy spectrum of all source components. It constrains the time-dependence of the maximum energy of the CRs at the shock, the time-dependence of the level of turbulence, and the diffusion coefficient immediately outside the SNR shock. While in agreement with the standard picture of DSA, the time-dependence of the maximum energy was found to be steeper than predicted, and the level of turbulence was found to change over the lifetime of the SNR.Key words: acceleration of particles / cosmic rays / gamma rays: general / gamma rays: ISM / ISM: clouds / ISM: supernova remnants★ Corresponding authors; e-mail: contact.magic@mpp.mpg.de, Published by EDP Sciences, Les Ulis

Published
2023

2. H.E.S.S. and MAGIC observations of a sudden cessation of a very-high-energy γ-ray flare in PKS 1510−089 in May 2016

Author

Abdalla, H. (H.), Adam, R. (R.), Aharonian, F. (F.), Benkhali, F. A. (F. Ait), Anguner, E. O. (E. O.), Arcaro, C. (C.), Armand, C. (C.), Armstrong, T. (T.), Ashkar, H. (H.), Backes, M. (M.), Baghmanyan, V. (V), Martins, V. B. (V. Barbosa), Barnacka, A. (A.), Barnard, M. (M.), Becherini, Y. (Y.), Berge, D. (D.), Bernlohr, K. (K.), Bi, B. (B.), Bottcher, M. (M.), Boisson, C. (C.), Bolmont, J. (J.), Bonnefoy, S. (S.), de Lavergne, M. d. (M. de Bony), Bregeon, J. (J.), Breuhaus, M. (M.), Brun, F. (F.), Brun, P. (P.), Bryan, M. (M.), Buchele, M. (M.), Bulik, T. (T.), Bylund, T. (T.), Caroff, S. (S.), Carosi, A. (A.), Casanova, S. (S.), Chand, T. (T.), Chandra, S. (S.), Chen, A. (A.), Cotter, G. (G.), Mbarubucyeye, J. D. (J. Damascene), Davids, I. D. (I. D.), Davies, J. (J.), Deil, C. (C.), Devin, J. (J.), DeWilt, P. (P.), Dirson, L. (L.), Djannati-Atai, A. (A.), Dmytriiev, A. (A.), Donath, A. (A.), Doroshenko, V. (V), Dyks, J. (J.), Egberts, K. (K.), Eichhorn, F. (F.), Einecke, S. (S.), Emery, G. (G.), Ernenwein, J.-P. (J-P), Feijen, K. (K.), Fegan, S. (S.), Fiasson, A. (A.), de Clairfontaine, G. F. (G. Fichet), Filipovic, M. (M.), Fontaine, G. (G.), Funk, S. (S.), Fuling, M. (M.), Gabici, S. (S.), Gallant, Y. A. (Y. A.), Giavitto, G. (G.), Giunti, L. (L.), Glawion, D. (D.), Glicenstein, J. F. (J. F.), Gottschall, D. (D.), Grondin, M.-H. (M-H), Hahn, J. (J.), Haupt, M. (M.), Hermann, G. (G.), Hinton, J. A. (J. A.), Hofmann, W. (W.), Hoischen, C. (C.), Holch, T. L. (T. L.), Holler, M. (M.), Horbe, M. (M.), Horns, D. (D.), Huber, D. (D.), Jamrozy, M. (M.), Jankowsky, D. (D.), Jankowsky, F. (F.), Jardin-Blicq, A. (A.), Joshi, V. (V), Jung-Richardt, I. (I), Kastendieck, M. A. (M. A.), Katarzynski, K. (K.), Katz, U. (U.), Khangulyan, D. (D.), Khelifi, B. (B.), Klepser, S. (S.), Kluzniak, W. (W.), Komin, N. (Nu), Konno, R. (R.), Kosack, K. (K.), Kostunin, D. (D.), Kreter, M. (M.), Lamanna, G. (G.), Lemiere, A. (A.), Lemoine-Goumard, M. (M.), Lenain, J.-P. (J-P), Levy, C. (C.), Lohse, T. (T.), Lypova, I. (I), Mackey, J. (J.), Majumdar, J. (J.), Malyshev, D. (D.), Marandon, V. (V), Marchegiani, P. (P.), Marcowith, A. (A.), Mares, A. (A.), Marti-Devesa, G. (G.), Marx, R. (R.), Maurin, G. (G.), Meintjes, P. J. (P. J.), Meyer, M. (M.), Mitchell, A. M. (A. M. W.), Moderski, R. (R.), Mohamed, M. (M.), Mohrmann, L. (L.), Montanari, A. (A.), Moore, C. (C.), Morris, P. (P.), Moulin, E. (E.), Muller, J. (J.), Murach, T. (T.), Nakashima, K. (K.), Nayerhoda, A. (A.), de Naurois, M. (M.), Ndiyavala, H. (H.), Niederwanger, F. (F.), Niemiec, D. (D.), Oakes, L. (L.), O'Brien, P. (P.), Odaka, H. (H.), Ohm, S. (S.), Olivera-Nieto, L. (L.), Wilhelmi, E. d. (E. de Ona), Ostrowski, M. (M.), Panter, M. (M.), Panny, S. (S.), Parsons, R. D. (R. D.), Peron, G. (G.), Peyaud, B. (B.), Piel, Q. (Q.), Pita, S. (S.), Poireau, V. (V), Noel, A. P. (A. Priyana), Prokhorov, D. A. (D. A.), Prokoph, H. (H.), Puhlhofer, G. (G.), Punch, M. (M.), Quirrenbach, A. (A.), Raab, S. (S.), Rauth, R. (R.), Reichherzer, P. (P.), Reimer, A. (A.), Reimer, O. (O.), Remy, Q. (Q.), Renaud, M. (M.), Rieger, F. (F.), Rinchiuso, L. (L.), Romoli, C. (C.), Rowell, G. (G.), Rudak, B. (B.), Ruiz-Velasco, E. (E.), Sahakian, V. (V), Sailer, S. (S.), Sanchez, D. A. (D. A.), Santangelo, A. (A.), Sasaki, M. (M.), Scalici, M. (M.), Schussler, F. (F.), Schutte, H. M. (H. M.), Schwanke, U. (U.), Schwemmer, S. (S.), Seglar-Arroyo, M. (M.), Senniappan, M. (M.), Seyffert, A. S. (A. S.), Shafi, N. (N.), Shiningayamwe, K. (K.), Simoni, R. (R.), Sinha, A. (A.), Sol, H. (H.), Specovius, A. (A.), Spencer, S. (S.), Sun, L. (L.), Steenkamp, R. (R.), Stegmann, C. (C.), Steinmassl, S. (S.), Steppa, C. (C.), Takahashi, T. (T.), Tavernier, T. (T.), Taylor, A. M. (A. M.), Terrier, R. (R.), Tiziani, D. (D.), Tluczykont, M. (M.), Tomankova, L. (L.), Trichard, C. (C.), Tsirou, M. (M.), Tuffs, R. (R.), Uchiyama, Y. (Y.), van der Walt, D. J. (D. J.), van Eldik, C. (C.), van Rensburg, C. (C.), van Soelen, B. (B.), Vasileiadis, G. (G.), Veh, J. (J.), Venter, C. (C.), Vincent, P. (P.), Vink, J. (J.), Volk, H. J. (H. J.), Vuillaume, T. (T.), Wadiasingh, Z. (Z.), Wagner, S. J. (S. J.), Watson, J. (J.), Werner, F. (F.), White, R. (R.), Wierzcholska, A. (A.), Wong, Y. W. (Yu W.), Yusafzai, A. (A.), Zacharias, M. (M.), Zanin, R. (R.), Zargaryan, D. (D.), Zdziarski, A. A. (A. A.), Zech, A. (A.), Zhu, S. J. (S. J.), Zorn, J. (J.), Zouari, S. (S.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Asano, K. (K.), Baack, D. (D.), Babic, A. (A.), Baquero, A. (A.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Gonzalez, J. B. (J. Becerra), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Espineira, E. D. (E. Do Souto), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Heckmann, L. (L.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovi, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Perennes, C. (C.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Priyadarshi, C. (C.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Truzzi, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Jorstad, S. G. (S. G.), Marscher, A. P. (A. P.), Boccardi, B. (B.), Casadio, C. (C.), Hodgson, J. (J.), Kim, J.-Y. (J-Y), Krichbaum, T. P. (T. P.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Traianou, E. (E.), Weaver, Z. R. (Z. R.), Abdalla, H. (H.), Adam, R. (R.), Aharonian, F. (F.), Benkhali, F. A. (F. Ait), Anguner, E. O. (E. O.), Arcaro, C. (C.), Armand, C. (C.), Armstrong, T. (T.), Ashkar, H. (H.), Backes, M. (M.), Baghmanyan, V. (V), Martins, V. B. (V. Barbosa), Barnacka, A. (A.), Barnard, M. (M.), Becherini, Y. (Y.), Berge, D. (D.), Bernlohr, K. (K.), Bi, B. (B.), Bottcher, M. (M.), Boisson, C. (C.), Bolmont, J. (J.), Bonnefoy, S. (S.), de Lavergne, M. d. (M. de Bony), Bregeon, J. (J.), Breuhaus, M. (M.), Brun, F. (F.), Brun, P. (P.), Bryan, M. (M.), Buchele, M. (M.), Bulik, T. (T.), Bylund, T. (T.), Caroff, S. (S.), Carosi, A. (A.), Casanova, S. (S.), Chand, T. (T.), Chandra, S. (S.), Chen, A. (A.), Cotter, G. (G.), Mbarubucyeye, J. D. (J. Damascene), Davids, I. D. (I. D.), Davies, J. (J.), Deil, C. (C.), Devin, J. (J.), DeWilt, P. (P.), Dirson, L. (L.), Djannati-Atai, A. (A.), Dmytriiev, A. (A.), Donath, A. (A.), Doroshenko, V. (V), Dyks, J. (J.), Egberts, K. (K.), Eichhorn, F. (F.), Einecke, S. (S.), Emery, G. (G.), Ernenwein, J.-P. (J-P), Feijen, K. (K.), Fegan, S. (S.), Fiasson, A. (A.), de Clairfontaine, G. F. (G. Fichet), Filipovic, M. (M.), Fontaine, G. (G.), Funk, S. (S.), Fuling, M. (M.), Gabici, S. (S.), Gallant, Y. A. (Y. A.), Giavitto, G. (G.), Giunti, L. (L.), Glawion, D. (D.), Glicenstein, J. F. (J. F.), Gottschall, D. (D.), Grondin, M.-H. (M-H), Hahn, J. (J.), Haupt, M. (M.), Hermann, G. (G.), Hinton, J. A. (J. A.), Hofmann, W. (W.), Hoischen, C. (C.), Holch, T. L. (T. L.), Holler, M. (M.), Horbe, M. (M.), Horns, D. (D.), Huber, D. (D.), Jamrozy, M. (M.), Jankowsky, D. (D.), Jankowsky, F. (F.), Jardin-Blicq, A. (A.), Joshi, V. (V), Jung-Richardt, I. (I), Kastendieck, M. A. (M. A.), Katarzynski, K. (K.), Katz, U. (U.), Khangulyan, D. (D.), Khelifi, B. (B.), Klepser, S. (S.), Kluzniak, W. (W.), Komin, N. (Nu), Konno, R. (R.), Kosack, K. (K.), Kostunin, D. (D.), Kreter, M. (M.), Lamanna, G. (G.), Lemiere, A. (A.), Lemoine-Goumard, M. (M.), Lenain, J.-P. (J-P), Levy, C. (C.), Lohse, T. (T.), Lypova, I. (I), Mackey, J. (J.), Majumdar, J. (J.), Malyshev, D. (D.), Marandon, V. (V), Marchegiani, P. (P.), Marcowith, A. (A.), Mares, A. (A.), Marti-Devesa, G. (G.), Marx, R. (R.), Maurin, G. (G.), Meintjes, P. J. (P. J.), Meyer, M. (M.), Mitchell, A. M. (A. M. W.), Moderski, R. (R.), Mohamed, M. (M.), Mohrmann, L. (L.), Montanari, A. (A.), Moore, C. (C.), Morris, P. (P.), Moulin, E. (E.), Muller, J. (J.), Murach, T. (T.), Nakashima, K. (K.), Nayerhoda, A. (A.), de Naurois, M. (M.), Ndiyavala, H. (H.), Niederwanger, F. (F.), Niemiec, D. (D.), Oakes, L. (L.), O'Brien, P. (P.), Odaka, H. (H.), Ohm, S. (S.), Olivera-Nieto, L. (L.), Wilhelmi, E. d. (E. de Ona), Ostrowski, M. (M.), Panter, M. (M.), Panny, S. (S.), Parsons, R. D. (R. D.), Peron, G. (G.), Peyaud, B. (B.), Piel, Q. (Q.), Pita, S. (S.), Poireau, V. (V), Noel, A. P. (A. Priyana), Prokhorov, D. A. (D. A.), Prokoph, H. (H.), Puhlhofer, G. (G.), Punch, M. (M.), Quirrenbach, A. (A.), Raab, S. (S.), Rauth, R. (R.), Reichherzer, P. (P.), Reimer, A. (A.), Reimer, O. (O.), Remy, Q. (Q.), Renaud, M. (M.), Rieger, F. (F.), Rinchiuso, L. (L.), Romoli, C. (C.), Rowell, G. (G.), Rudak, B. (B.), Ruiz-Velasco, E. (E.), Sahakian, V. (V), Sailer, S. (S.), Sanchez, D. A. (D. A.), Santangelo, A. (A.), Sasaki, M. (M.), Scalici, M. (M.), Schussler, F. (F.), Schutte, H. M. (H. M.), Schwanke, U. (U.), Schwemmer, S. (S.), Seglar-Arroyo, M. (M.), Senniappan, M. (M.), Seyffert, A. S. (A. S.), Shafi, N. (N.), Shiningayamwe, K. (K.), Simoni, R. (R.), Sinha, A. (A.), Sol, H. (H.), Specovius, A. (A.), Spencer, S. (S.), Sun, L. (L.), Steenkamp, R. (R.), Stegmann, C. (C.), Steinmassl, S. (S.), Steppa, C. (C.), Takahashi, T. (T.), Tavernier, T. (T.), Taylor, A. M. (A. M.), Terrier, R. (R.), Tiziani, D. (D.), Tluczykont, M. (M.), Tomankova, L. (L.), Trichard, C. (C.), Tsirou, M. (M.), Tuffs, R. (R.), Uchiyama, Y. (Y.), van der Walt, D. J. (D. J.), van Eldik, C. (C.), van Rensburg, C. (C.), van Soelen, B. (B.), Vasileiadis, G. (G.), Veh, J. (J.), Venter, C. (C.), Vincent, P. (P.), Vink, J. (J.), Volk, H. J. (H. J.), Vuillaume, T. (T.), Wadiasingh, Z. (Z.), Wagner, S. J. (S. J.), Watson, J. (J.), Werner, F. (F.), White, R. (R.), Wierzcholska, A. (A.), Wong, Y. W. (Yu W.), Yusafzai, A. (A.), Zacharias, M. (M.), Zanin, R. (R.), Zargaryan, D. (D.), Zdziarski, A. A. (A. A.), Zech, A. (A.), Zhu, S. J. (S. J.), Zorn, J. (J.), Zouari, S. (S.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Asano, K. (K.), Baack, D. (D.), Babic, A. (A.), Baquero, A. (A.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Gonzalez, J. B. (J. Becerra), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Espineira, E. D. (E. Do Souto), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Heckmann, L. (L.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovi, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Perennes, C. (C.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Priyadarshi, C. (C.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Truzzi, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Jorstad, S. G. (S. G.), Marscher, A. P. (A. P.), Boccardi, B. (B.), Casadio, C. (C.), Hodgson, J. (J.), Kim, J.-Y. (J-Y), Krichbaum, T. P. (T. P.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Traianou, E. (E.), and Weaver, Z. R. (Z. R.)

Abstract

The flat spectrum radio quasar (FSRQ) PKS 1510−089 is known for its complex multiwavelength behaviour and it is one of only a few FSRQs detected in very-high-energy (VHE, E > 100 GeV) γ rays. The VHE γ-ray observations with H.E.S.S. and MAGIC in late May and early June 2016 resulted in the detection of an unprecedented flare, which revealed, for the first time, VHE γ-ray intranight variability for this source. While a common variability timescale of 1.5 h has been found, there is a significant deviation near the end of the flare, with a timescale of ∼20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, a curvature was detected in the VHE γ-ray spectrum of PKS 1510–089, which can be fully explained by the absorption on the part of the extragalactic background light. Optical R-band observations with ATOM revealed a counterpart of the γ-ray flare, even though the detailed flux evolution differs from the VHE γ-ray light curve. Interestingly, a steep flux decrease was observed at the same time as the cessation of the VHE γ-ray flare. In the high-energy (HE, E > 100 MeV) γ-ray band, only a moderate flux increase was observed with Fermi-LAT, while the HE γ-ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the γ-ray spectrum indicates that the emission region is located outside of the BLR. Radio very-long-baseline interferometry observations reveal a fast-moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located ∼50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this is indeed a true correlation, the VHE γ rays must have been produced far down in the jet, where turbulent plasma crosses a standing shock.

Published
2021

3. VHE gamma-ray detection of FSRQ QSO B1420+326 and modeling of its enhanced broadband state in 2020

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Artero, M. (M.), Asano, K. (K.), Baack, D. (D.), Babic, A. (A.), Baquero, A. (A.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Bernardos, M. (M.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Delgado Mendez, C. (C.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, J. G. (J. G.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Heckmann, L. (L.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jormanainen, J. (J.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez-Coto, R. (R.), Lopez-Moya, M. (M.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V.), Moretti, E. (E.), Neustroev, V. (V.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Paiano, S. (S.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Perennes, C. (C.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Priyadarshi, C. (C.), Puljak, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Saturni, F. G. (F. G.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Truzzi, S. (S.), Tutone, A. (A.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I.), Will, M. (M.), Zaric, D. (D.), Angioni, R. (R.), D'Ammando, F. (F.), Ciprini, S. (S.), Cheung, C. C. (C. C.), Orienti, M. (M.), Pacciani, L. (L.), Prajapati, P. (P.), Kumar, P. (P.), Ganesh, S. (S.), Kurtenkov, A. (A.), Marchini, A. (A.), Carrasco, L. (L.), Escobedo, G. (G.), Porras, A. (A.), Recillas, E. (E.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Berton, M. (M.), Tammi, J. (J.), Vera, R. J. (R. J. C.), Jorstad, S. G. (S. G.), Marscher, A. P. (A. P.), Weaver, Z. R. (Z. R.), Hart, M. (M.), Hallum, M. K. (M. K.), Larionov, V. M. (V. M.), Borman, G. A. (G. A.), Grishina, T. S. (T. S.), Kopatskaya, E. N. (E. N.), Larionova, E. G. (E. G.), Nikiforova, A. A. (A. A.), Morozova, D. A. (D. A.), Savchenko, S. S. (S. S.), Troitskaya, Y. V. (Yu. V.), Troitsky, I. S. (I. S.), Vasilyev, A. A. (A. A.), Hodges, M. (M.), Hovatta, T. (T.), Kiehlmann, S. (S.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Reeves, R. (R.), Pearson, T. J. (T. J.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Artero, M. (M.), Asano, K. (K.), Baack, D. (D.), Babic, A. (A.), Baquero, A. (A.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Bernardos, M. (M.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Delgado Mendez, C. (C.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, J. G. (J. G.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Heckmann, L. (L.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jormanainen, J. (J.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez-Coto, R. (R.), Lopez-Moya, M. (M.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V.), Moretti, E. (E.), Neustroev, V. (V.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Paiano, S. (S.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Perennes, C. (C.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Priyadarshi, C. (C.), Puljak, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Saturni, F. G. (F. G.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Truzzi, S. (S.), Tutone, A. (A.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I.), Will, M. (M.), Zaric, D. (D.), Angioni, R. (R.), D'Ammando, F. (F.), Ciprini, S. (S.), Cheung, C. C. (C. C.), Orienti, M. (M.), Pacciani, L. (L.), Prajapati, P. (P.), Kumar, P. (P.), Ganesh, S. (S.), Kurtenkov, A. (A.), Marchini, A. (A.), Carrasco, L. (L.), Escobedo, G. (G.), Porras, A. (A.), Recillas, E. (E.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Berton, M. (M.), Tammi, J. (J.), Vera, R. J. (R. J. C.), Jorstad, S. G. (S. G.), Marscher, A. P. (A. P.), Weaver, Z. R. (Z. R.), Hart, M. (M.), Hallum, M. K. (M. K.), Larionov, V. M. (V. M.), Borman, G. A. (G. A.), Grishina, T. S. (T. S.), Kopatskaya, E. N. (E. N.), Larionova, E. G. (E. G.), Nikiforova, A. A. (A. A.), Morozova, D. A. (D. A.), Savchenko, S. S. (S. S.), Troitskaya, Y. V. (Yu. V.), Troitsky, I. S. (I. S.), Vasilyev, A. A. (A. A.), Hodges, M. (M.), Hovatta, T. (T.), Kiehlmann, S. (S.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Reeves, R. (R.), and Pearson, T. J. (T. J.)

Abstract

Context.: QSO B1420+326 is a blazar classified as a flat-spectrum radio quasar (FSRQ). At the beginning of the year 2020, it was found to be in an enhanced flux state and an extensive multiwavelength campaign allowed us to trace the evolution of the flare. Aims.: We search for very high-energy (VHE) gamma-ray emission from QSO B1420+326 during this flaring state. We aim to characterize and model the broadband emission of the source over different phases of the flare. Methods: The source was observed with a number of instruments in radio, near-infrared, optical (including polarimetry and spectroscopy), ultraviolet, X-ray, and gamma-ray bands. We use dedicated optical spectroscopy results to estimate the accretion disk and the dust torus luminosity. We performed spectral energy distribution modeling in the framework of combined synchrotron-self-Compton and external Compton scenario in which the electron energy distribution is partially determined from acceleration and cooling processes. Results: During the enhanced state, the flux of both SED components of QSO B1420+326 drastically increased and the peaks were shifted to higher energies. Follow-up observations with the MAGIC telescopes led to the detection of VHE gamma-ray emission from this source, making it one of only a handful of FSRQs known in this energy range. Modeling allows us to constrain the evolution of the magnetic field and electron energy distribution in the emission region. The gamma-ray flare was accompanied by a rotation of the optical polarization vector during a low -polarization state. Also, a new superluminal radio knot contemporaneously appeared in the radio image of the jet. The optical spectroscopy shows a prominent FeII bump with flux evolving together with the continuum emission and a MgII line with varying equivalent width.

Published
2021

4. MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, A. (A.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), Chilingaryan, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Huetten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kerszberg, D. (D.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Micanovic, S. (S.), Miceli, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Nozaki, S. (S.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Tsujimoto, S. (S.), Vagelli, V. (V.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), and Zaric, D. (D.)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, supernova remnants [ISM], Astrophysics::Instrumentation and Methods for Astrophysics, observational [methods], general [gamma rays]
Abstract

Aims: We measure the Crab Nebula γ-ray spectral energy distribution in the ~100 TeV energy domain and test the validity of existing leptonic emission models at these high energies. Methods: We used the novel very large zenith angle observations with the MAGIC telescope system to increase the collection area above 10 TeV. We also developed an auxiliary procedure of monitoring atmospheric transmission in order to assure proper calibration of the accumulated data. This employs recording optical images of the stellar field next to the source position, which provides a better than 10% accuracy for the transmission measurements. Results: We demonstrate that MAGIC very large zenith angle observations yield a collection area larger than a square kilometer. In only ~ 56 h of observations, we detect the γ-ray emission from the Crab Nebula up to 100 TeV, thus providing the highest energy measurement of this source to date with Imaging Atmospheric Cherenkov Telescopes. Comparing accumulated and archival MAGIC and Fermi/LAT data with some of the existing emission models, we find that none of them provides an accurate description of the 1 GeV to 100 TeV γ-ray signal.

Published
2020

5. Broadband characterisation of the very intense TeV flares of the blazar 1ES 1959+650 in 2016

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Micanovic, S. (S.), Miceli, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V.), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), Nozaki, S. (S.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Will, M. (M.), Zaric, D. (D.), Hayashida, M. (M.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Micanovic, S. (S.), Miceli, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V.), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), Nozaki, S. (S.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Will, M. (M.), Zaric, D. (D.), and Hayashida, M. (M.)

Abstract

1ES 1959+650 is a bright TeV high-frequency-peaked BL Lac object exhibiting interesting features like “orphan” TeV flares and broad emission in the high-energy regime that are difficult to interpret using conventional one-zone Synchrotron Self-Compton (SSC) scenarios. We report the results from the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observations in 2016 along with the multi-wavelength data from the Fermi Large Area Telescope (LAT) and Swift instruments. MAGIC observed 1ES 1959+650 with different emission levels in the very-high-energy (VHE, E > 100 GeV) γ-ray band during 2016. In the long-term data, the X-ray spectrum becomes harder with increasing flux and a hint of a similar trend is also visible in the VHE band. An exceptionally high VHE flux reaching ∼3 times the Crab Nebula flux was measured by MAGIC on the 13 and 14 of June, and 1 July 2016 (the highest flux observed since 2002). During these flares, the high-energy peak of the spectral energy distribution (SED) lies in the VHE domain and extends up to several TeV. The spectrum in the γ-ray (both Fermi-LAT and VHE bands) and the X-ray bands are quite hard. On 13 June and 1 July 2016, the source showed rapid variations in the VHE flux within timescales of less than an hour. A simple one-zone SSC model can describe the data during the flares requiring moderate to large values of the Doppler factors (δ ≥ 30−60). Alternatively, the high-energy peak of the SED can be explained by a purely hadronic model attributed to proton-synchrotron radiation with jet power Ljet ∼ 10⁴⁶ erg s⁻¹ and under high values of the magnetic field strength (∼100 G) and maximum proton energy (∼few EeV). Mixed lepto-hadronic models require super-Eddington values of the jet power. We conclude that it is difficult to get detectable neutrino emission from the source during the extreme VHE flaring period of 2016.

Published
2020

6. MAGIC observations of the diffuse γ-ray emission in the vicinity of the Galactic center

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), Chilingaryan, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kerszberg, D. (D.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Micanovic, S. (S.), Miceli, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Nozaki, S. (S.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Tsujimoto, S. (S.), Vagelli, V. (V.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chai, Y. (Y.), Chilingaryan, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Do Souto Espineira, E. (E.), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Godinovic, N. (N.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Hutten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kerszberg, D. (D.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Machado de Oliveira Fraga, B. (B.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Micanovic, S. (S.), Miceli, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Nozaki, S. (S.), Paiano, S. (S.), Palacio, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), Tsujimoto, S. (S.), Vagelli, V. (V.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), and Zaric, D. (D.)

Abstract

Aims: In the presence of a sufficient amount of target material, γ-rays can be used as a tracer in the search for sources of Galactic cosmic rays (CRs). Here we present deep observations of the Galactic center (GC) region with the MAGIC telescopes and use them to infer the underlying CR distribution and to study the alleged PeV proton accelerator at the center of our Galaxy. Methods: We used data from ≈100 h observations of the GC region conducted with the MAGIC telescopes over five years (from 2012 to 2017). Those were collected at high zenith angles (58−70 deg), leading to a larger energy threshold, but also an increased effective collection area compared to low zenith observations. Using recently developed software tools, we derived the instrument response and background models required for extracting the diffuse emission in the region. We used existing measurements of the gas distribution in the GC region to derive the underlying distribution of CRs. We present a discussion of the associated biases and limitations of such an approach. Results: We obtain a significant detection for all four model components used to fit our data (Sgr A*, “Arc”, G0.9+0.1, and an extended component for the Galactic Ridge). We observe no significant difference between the γ-ray spectra of the immediate GC surroundings, which we model as a point source (Sgr A*) and the Galactic Ridge. The latter can be described as a power-law with index 2 and an exponential cut-off at around 20 TeV with the significance of the cut-off being only 2σ. The derived cosmic-ray profile hints to a peak at the GC position and with a measured profile index of 1.2 ± 0.3 is consistent with the 1/r radial distance scaling law, which supports the hypothesis of a CR accelerator at the GC. We argue that the measurements of this profile are presently limited by our knowledge of the gas distribution in the GC vicinity.

Published
2020

7. Testing two-component models on very high-energy gamma-ray-emitting BL Lac objects

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Gonzalez, J. B. (J. Becerra), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Espineira, E. D. (E. Do Souto), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Huetten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Nievas-Rosillo, M. (M.), Arcaro, C. (C.), D'Ammando, F. (F.), de Palma, F. (F.), Hodges, M. (M.), Hovatta, T. (T.), Kiehlmann, S. (S.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Reeves, R. (R.), Takalo, L. (L.), Reinthal, R. (R.), Jormanainen, J. (J.), Wierda, F. (F.), Wagner, S. M. (S. M.), Berdyugin, A. (A.), Nabizadeh, A. (A.), Sheshvan, N. T. (N. Talebpour), Oksanen, A. (A.), Bachev, R. (R.), Strigachev, A. (A.), Kehusmaa, P. (P.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Gonzalez, J. B. (J. Becerra), Bednarek, W. (W.), Bellizzi, L. (L.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Bosnjak, Z. (Z.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cerruti, M. (M.), Chai, Y. (Y.), Chilingarian, A. (A.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, U. (U.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Amico, G. (G.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Depaoli, D. (D.), Di Pierro, F. (F.), Di Venere, L. (L.), Espineira, E. D. (E. Do Souto), Prester, D. D. (D. Dominis), Donini, A. (A.), Dorner, D. (D.), Doro, M. (M.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Ferrara, G. (G.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Fukami, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giglietto, N. (N.), Giordano, F. (F.), Gliwny, P. (P.), Godinovic, N. (N.), Green, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Huetten, M. (M.), Inada, T. (T.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Jouvin, L. (L.), Kajiwara, Y. (Y.), Karjalainen, M. (M.), Kerszberg, D. (D.), Kobayashi, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Coto, R. (R.), Lopez-Oramas, A. (A.), Loporchio, S. (S.), Fraga, B. M. (B. Machado de Oliveira), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Mazin, D. (D.), Mender, S. (S.), Micanovic, S. (S.), Miceli, D. (D.), Miener, T. (T.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Morcuende, D. (D.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nozaki, S. (S.), Ohtani, Y. (Y.), Oka, T. (T.), Otero-Santos, J. (J.), Palatiello, M. (M.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pavletic, L. (L.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Sakurai, S. (S.), Satalecka, K. (K.), Schleicher, B. (B.), Schmidt, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Spolon, A. (A.), Stamerra, A. (A.), Strom, D. (D.), Strzys, M. (M.), Suda, Y. (Y.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tosti, L. (L.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Ventura, S. (S.), Verguilov, V. (V.), Vigorito, C. F. (C. F.), Vitale, V. (V.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Nievas-Rosillo, M. (M.), Arcaro, C. (C.), D'Ammando, F. (F.), de Palma, F. (F.), Hodges, M. (M.), Hovatta, T. (T.), Kiehlmann, S. (S.), Max-Moerbeck, W. (W.), Readhead, A. C. (A. C. S.), Reeves, R. (R.), Takalo, L. (L.), Reinthal, R. (R.), Jormanainen, J. (J.), Wierda, F. (F.), Wagner, S. M. (S. M.), Berdyugin, A. (A.), Nabizadeh, A. (A.), Sheshvan, N. T. (N. Talebpour), Oksanen, A. (A.), Bachev, R. (R.), Strigachev, A. (A.), and Kehusmaa, P. (P.)

Abstract

Context: It has become evident that one-zone synchrotron self-Compton models are not always adequate for very high-energy (VHE) gamma-ray-emitting blazars. While two-component models perform better, they are difficult to constrain due to the large number of free parameters. Aims: In this work, we make a first attempt at taking into account the observational constraints from very long baseline interferometry (VLBI) data, long-term light curves (radio, optical, and X-rays), and optical polarisation to limit the parameter space for a two-component model and test whether or not it can still reproduce the observed spectral energy distribution (SED) of the blazars. Methods: We selected five TeV BL Lac objects based on the availability of VHE gamma-ray and optical polarisation data. We collected constraints for the jet parameters from VLBI observations. We evaluated the contributions of the two components to the optical flux by means of decomposition of long-term radio and optical light curves as well as modelling of the optical polarisation variability of the objects. We selected eight epochs for these five objects based on the variability observed at VHE gamma rays, for which we constructed the SEDs that we then modelled with a two-component model. Results: We found parameter sets which can reproduce the broadband SED of the sources in the framework of two-component models considering all available observational constraints from VLBI observations. Moreover, the constraints obtained from the long-term behaviour of the sources in the lower energy bands could be used to determine the region where the emission in each band originates. Finally, we attempt to use optical polarisation data to shed new light on the behaviour of the two components in the optical band. Our observationally constrained two-component model allows explanation of the entire SED from radio to VHE with two co-located emission regions.

Published
2020

8. Study of the variable broadband emission of Markarian 501 during the most extreme Swift X-ray activity

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Doro, M. (M.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), de Oliveira Fraga, B. M. (B. Machado), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Arbet-Engels, A. (A.), Baack, D. (D.), Balbo, M. (M.), Biland, A. (A.), Blank, M. (M.), Bretz, T. (T.), Bruegge, K. (K.), Bulinski, M. (M.), Buss, J. (J.), Doerr, M. (M.), Dorner, D. (D.), Einecke, S. (S.), Elsaesser, D. (D.), Hildebrand, D. (D.), Linhoff, L. (L.), Mannheim, K. (K.), Mueller, S. (S.), Neise, D. (D.), Neronov, A. (A.), Noethe, M. (M.), Paravac, A. (A.), Rhode, W. (W.), Schleicher, B. (B.), Schulz, F. (F.), Sedlaczek, K. (K.), Shukla, A. (A.), Sliusar, V. (V), von Willert, E. (E.), Walter, R. (R.), Wendel, C. (C.), Tramacere, A. (A.), Lien, A. (A.), Perri, M. (M.), Verrecchia, F. (F.), Armas Padilla, M. (M.), Leto, C. (C.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Tammi, J. (J.), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Babic, A. (A.), Banerjee, B. (B.), de Almeida, U. B. (U. Barres), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Blanch, O. (O.), Bonnoli, G. (G.), Busetto, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Doro, M. (M.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), de Oliveira Fraga, B. M. (B. Machado), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Mallamaci, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Sahakyan, N. (N.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), Arbet-Engels, A. (A.), Baack, D. (D.), Balbo, M. (M.), Biland, A. (A.), Blank, M. (M.), Bretz, T. (T.), Bruegge, K. (K.), Bulinski, M. (M.), Buss, J. (J.), Doerr, M. (M.), Dorner, D. (D.), Einecke, S. (S.), Elsaesser, D. (D.), Hildebrand, D. (D.), Linhoff, L. (L.), Mannheim, K. (K.), Mueller, S. (S.), Neise, D. (D.), Neronov, A. (A.), Noethe, M. (M.), Paravac, A. (A.), Rhode, W. (W.), Schleicher, B. (B.), Schulz, F. (F.), Sedlaczek, K. (K.), Shukla, A. (A.), Sliusar, V. (V), von Willert, E. (E.), Walter, R. (R.), Wendel, C. (C.), Tramacere, A. (A.), Lien, A. (A.), Perri, M. (M.), Verrecchia, F. (F.), Armas Padilla, M. (M.), Leto, C. (C.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), and Tammi, J. (J.)

Abstract

Context: Markarian 501 (Mrk 501) is a very high-energy (VHE) gamma-ray blazar located at z = 0.034, which is regularly monitored by a wide range of multi-wavelength instruments, from radio to VHE gamma rays. During a period of almost two weeks in July 2014, the highest X-ray activity of Mrk 501 was observed in ∼14 years of operation of the Neil Gehrels Swift Gamma-ray Burst Observatory. Aims: We characterize the broadband variability of Mrk 501 from radio to VHE gamma rays during the most extreme X-ray activity measured in the last 14 years, and evaluate whether it can be interpreted within theoretical scenarios widely used to explain the broadband emission from blazars. Methods: The emission of Mrk 501 was measured at radio with Metsähovi, at optical–UV with KVA and Swift/UVOT, at X-ray with Swift/XRT and Swift/BAT, at gamma ray with Fermi-LAT, and at VHE gamma rays with the FACT and MAGIC telescopes. The multi-band variability and correlations were quantified, and the broadband spectral energy distributions (SEDs) were compared with predictions from theoretical models. Results: The VHE emission of Mrk 501 was found to be elevated during the X-ray outburst, with a gamma-ray flux above 0.15 TeV varying from ∼0.5 to ∼2 times the Crab nebula flux. The X-ray and VHE emission both varied on timescales of 1 day and were found to be correlated. We measured a general increase in the fractional variability with energy, with the VHE variability being twice as large as the X-ray variability. The temporal evolution of the most prominent and variable segments of the SED, characterized on a day-by-day basis from 2014 July 16 to 2014 July 31, is described with a one-zone synchrotron self-Compton model with variations in the break energy of the electron energy distribution (EED), and with some adjustments in the magnetic field strength and spectral shape of the EED. These results suggest that the main flux variations during this extreme X-ray outburst are produced by the

Published
2020

9. Gamma-ray flaring activity of NGC 1275 in 2016-2017 measured by MAGIC

Author

Ansoldi, S., Antonelli, L. A., Bednarek, W., Niedzwiecki, A., Rosillo, M. Nievas, Nigro, Cosimo, Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Bernardini, E., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peñil, P., Peresano, M., Persic, M., Pfrang, Konstantin Johannes, Moroni, P. G. Prada, Prandini, E., Berse, R. Ch, Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Saito, T., Berti, A., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takahashi, M., Tavecchio, F., Bhattacharyya, W., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Bigongiari, C., Zarić, D., Glawion, D., Takalo, L. O., Jormanainen, J., Magic, Collaboration, Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Arcaro, C., Ceribella, G., Chatterjee, A., SIDIKA MERVE COLAK, Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., D Elia, V., Baack, D., Da Vela, P., Dazzi, F., Angelis, A., Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Domínguez, A., Prester, D. Dominis, Dorner, D., Babić, A., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Banerjee, B., Font, L., Fruck, C., Galindo, D., Gallozzi, S., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Gora, D., Bangale, P., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hoang, J., Hose, J., Hrupec, D., Ishio, K., Almeida, U. Barres, Konno, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., Barrio, J. A., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., González, J. Becerra, Mazin, D., Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Nagayoshi, T., Neustroev, V., Ansoldi, S., Antonelli, L. A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bernardini, E., Berse, R. Ch., Berti, A., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., 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., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hoang, J., Hose, J., Hrupec, D., Ishio, K., Konno, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Nagayoshi, T., 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., Pfrang, K., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., Vanzo, G., Vazquez Acosta, M., Vovk, I., Ward, J. E., Will, M., Zarić, D., Glawion, D., Takalo, L. O., and Jormanainen, J.

Subjects
Galaxies: active, Galaxies: individual: NGC 1275, Galaxies: jets, Gamma rays: galaxies, Astronomy and Astrophysics, Space and Planetary Science, Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, jets [galaxies], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, jet [Galaxies], law.invention, law, 0103 physical sciences, gamma rays: galaxies, MAGIC (telescope), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), galaxies: jets, galaxies: individual: NGC 1275, galaxie [Gamma rays], 010308 nuclear & particles physics, Gamma ray, Astronomy and Astrophysic, Light curve, Monitoring program, Black hole, Crab Nebula, 13. Climate action, active [galaxies], galaxies [gamma rays], ddc:520, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, individual: NGC 1275 [galaxies], Flare
Abstract

We report on the detection of flaring activity from the Fanaroff-Riley I radio galaxy NGC 1275 in very-high-energy (VHE, E $>$ 100 GeV) gamma rays with the MAGIC telescopes. Observations were performed between 2016 September and 2017 February as part of a monitoring program. The brightest outburst with $\sim1.5$ times the Crab Nebula flux above 100 GeV (C.U.) was observed during the night between 2016 December 31 and 2017 January 1 (fifty times higher than the mean previously measured in two observational campaigns between 2009 and 2011). Significant variability of the day-by-day light curve was measured, the shortest flux-doubling time-scales was found to be of $(611\pm101)$ min. The combined spectrum of the MAGIC data during the strongest flare state and simultaneous data from the Fermi-LAT around 2017 January 1 follows a power-law with an exponential cutoff at the energy $(492\pm35)$ GeV. Simultaneous optical flux density measurements in the R-band obtained with the KVA telescope are also presented and the correlation between the optical and gamma-ray emission is investigated. Due to possible internal pair-production, the fast flux variability constrains the Doppler factor to values which are inconsistent with a large viewing angle as observed in the radio band. We investigate different scenarios for the explanation of fast gamma-ray variability, namely emission from: magnetospheric gaps, relativistic blobs propagating in the jet (mini-jets) or external cloud (or star) entering the jet. We find that the only plausible model to account for the luminosities here observed would be the production of gamma rays in a magnetospheric gap around the central black hole only in the eventuality of an enhancement of the magnetic field threading the hole from its equipartition value with the gas pressure in the accretion flow., accepted for publications in Astronomy and Astrophysics

Published
2018

10. A fast, very-high-energy γ-ray flare from BL Lacertae during a period of multi-wavelength activity in June 2015

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), D'Ammando, F. (F.), Hada, K. (K.), Jorstad, S. (S.), Marscher, A. P. (A. P.), Mobeen, M. Z. (M. Z.), Hovatta, T. (T.), Larionov, V. M. (V. M.), Borman, G. A. (G. A.), Grishina, T. S. (T. S.), Kopatskaya, E. N. (E. N.), Morozova, D. A. (D. A.), Nikiforova, A. A. (A. A.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), Agudo, I. (I), Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M., V), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Noethe, M. (M.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I), Garcia, J. R. (J. R.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I), Will, M. (M.), Zaric, D. (D.), D'Ammando, F. (F.), Hada, K. (K.), Jorstad, S. (S.), Marscher, A. P. (A. P.), Mobeen, M. Z. (M. Z.), Hovatta, T. (T.), Larionov, V. M. (V. M.), Borman, G. A. (G. A.), Grishina, T. S. (T. S.), Kopatskaya, E. N. (E. N.), Morozova, D. A. (D. A.), Nikiforova, A. A. (A. A.), Lahteenmaki, A. (A.), Tornikoski, M. (M.), and Agudo, I. (I)

Abstract

The mechanisms producing fast variability of the γ-ray emission in active galactic nuclei (AGNs) are under debate. The MAGIC telescopes detected a fast, very-high-energy (VHE, E > 100 GeV) γ-ray flare from BL Lacertae on 2015 June 15. The flare had a maximum flux of (1.5 ± 0.3) × 10−10 photons cm−2 s−1 and halving time of 26 ± 8 min. The MAGIC observations were triggered by a high state in the optical and high-energy (HE, E > 100 MeV) γ-ray bands. In this paper we present the MAGIC VHE γ-ray data together with multi-wavelength data from radio, optical, X-rays, and HE γ rays from 2015 May 1 to July 31. Well-sampled multi-wavelength data allow us to study the variability in detail and compare it to the other epochs when fast, VHE γ-ray flares have been detected from this source. Interestingly, we find that the behaviour in radio, optical, X-rays, and HE γ-rays is very similar to two other observed VHE γ-ray flares. In particular, also during this flare there was an indication of rotation of the optical polarization angle and of activity at the 43 GHz core. These repeating patterns indicate a connection between the three events. We also test modelling of the spectral energy distribution based on constraints from the light curves and VLBA observations, with two different geometrical setups of two-zone inverse Compton models. In addition we model the γ-ray data with the star-jet interaction model. We find that all of the tested emission models are compatible with the fast VHE γ-ray flare, but all have some tension with the multi-wavelength observations.

Published
2019

11. Towards open and reproducible multi-instrument analysis in gamma-ray astronomy

Author

Helmholtz Association, German Research Foundation, European Commission, Nigro, C., Deil, C., Zanin, R., Hassan, T., King, J., Ruíz, José Enrique, Saha, L., Terrier, R., Brügge, K., Nöthe, M., Bird, R., Lin, T.T.Y., Aleksic, J., Boisson, Catherine, Contreras, J.L., Donath, A., Jouvin, L., Kelley-Hoskins, N., Khelifi, B., Kosack, K., Rico, J., Sinha, A., Helmholtz Association, German Research Foundation, European Commission, Nigro, C., Deil, C., Zanin, R., Hassan, T., King, J., Ruíz, José Enrique, Saha, L., Terrier, R., Brügge, K., Nöthe, M., Bird, R., Lin, T.T.Y., Aleksic, J., Boisson, Catherine, Contreras, J.L., Donath, A., Jouvin, L., Kelley-Hoskins, N., Khelifi, B., Kosack, K., Rico, J., and Sinha, A.

Abstract

The analysis and combination of data from different gamma-ray instruments involves the use of collaboration proprietary software and case-by-case methods. The effort of defining a common data format for high-level data, namely event lists and instrument response functions (IRFs), has recently started for very-high-energy gamma-ray instruments, driven by the upcoming Cherenkov Telescope Array (CTA). In this work we implemented this prototypical data format for a small set of MAGIC, VERITAS, FACT, and H.E.S.S. Crab nebula observations, and we analyzed them with the open-source gammapy software package. By combining data from Fermi-LAT, and from four of the currently operating imaging atmospheric Cherenkov telescopes, we produced a joint maximum likelihood fit of the Crab nebula spectrum. Aspects of the statistical errors and the evaluation of systematic uncertainty are also commented upon, along with the release format of spectral measurements. The results presented in this work are obtained using open-access on-line assets that allow for a long-term reproducibility of the results.© ESO 2019.

Published
2019

12. Detection of persistent VHE gamma-ray emission from PKS 1510–089 by the MAGIC telescopes during low states between 2012 and 2017

Author

Acciari, V. A. (V. A.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Engels, A. A. (A. Arbet), Arcaro, C. (C.), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Bednarek, W. (W.), Bernardini, E. (E.), Berti, A. (A.), Besenrieder, J. (J.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Cikota, S. (S.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Do Souto Espinera, E. (E.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Kuvezdic, D. (D.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Lopez-Oramas, A. (A.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Molina, E. (E.), Moralejo, A. (A.), Moreno, V. (V.), Moretti, E. (E.), Munar-Adrover, P. (P.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Garcia, J. R. (J. R.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Somero, A. (A.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), van Scherpenberg, J. (J.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zari, D. (D.), Becerra Gonzalez, J. (J.), Raiteri, C. M. (C. M.), Sandrinelli, A. (A.), Hovatta, T. (T.), Kiehlmann, S. (S.), Max-Moerbeck, W. (W.), Tornikoski, M. (M.), Lahteenmaki, A. (A.), Tammi, J. (J.), Ramakrishnan, V. (V.), Thum, C. (C.), Agudo, I. (I.), Molina, S. N. (S. N.), Gomez, J. L. (J. L.), Fuentes, A. (A.), Casadio, C. (C.), Traianou, E. (E.), Myserlis, I. (I.), and Kim, J. -. (J. -Y.)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, individual: PKS 1510–089 [quasars], active [galaxies], galaxies [gamma rays], jets [galaxies], Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

Context: 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 (9.5σ) VHE gamma-ray emission at the level of (4.27 ± 0.61stat) × 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.

Published
2018

13. Overview of non-transient γ-ray binaries and prospects for the Cherenkov Telescope Array

Author

Chernyakova, M., primary, Malyshev, D., additional, Paizis, A., additional, La Palombara, N., additional, Balbo, M., additional, Walter, R., additional, Hnatyk, B., additional, van Soelen, B., additional, Romano, P., additional, Munar-Adrover, P., additional, Vovk, Ie., additional, Piano, G., additional, Capitanio, F., additional, Falceta-Gonçalves, D., additional, Landoni, M., additional, Luque-Escamilla, P. L., additional, Martí, J., additional, Paredes, J. M., additional, Ribó, M., additional, Safi-Harb, S., additional, Saha, L., additional, Sidoli, L., additional, and Vercellone, S., additional

Published
2019
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14. Towards open and reproducible multi-instrument analysis in gamma-ray astronomy

Author

Nigro, C., primary, Deil, C., additional, Zanin, R., additional, Hassan, T., additional, King, J., additional, Ruiz, J. E., additional, Saha, L., additional, Terrier, R., additional, Brügge, K., additional, Nöthe, M., additional, Bird, R., additional, Lin, T. T. Y., additional, Aleksić, J., additional, Boisson, C., additional, Contreras, J. L., additional, Donath, A., additional, Jouvin, L., additional, Kelley-Hoskins, N., additional, Khelifi, B., additional, Kosack, K., additional, Rico, J., additional, and Sinha, A., additional

Published
2019
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15. Gamma-ray flaring activity of NGC1275 in 2016–2017 measured by MAGIC

Author

Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Arcaro, C. (C.), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berse, R. C. (R. Ch.), Berti, A. (A.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chatterjee, A. (A.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), Cumani, P. (P.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Gora, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Hayashida, M. (M.), Herrera, J. (J.), Hoang, J. (J.), Hose, J. (J.), Hrupec, D. (D.), Ishio, K. (K.), Konno, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Mielke, K. (K.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Moralejo, A. (A.), Moreno, V. (V.), Moretti, E. (E.), Nagayoshi, T. (T.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Pfrang, K. (K.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Garcia, J. R. (J. R.), Reichardt, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), Glawion, D. (D.), Takalo, L. O. (L. O.), Jormanainen, J. (J.), Ansoldi, S. (S.), Antonelli, L. A. (L. A.), Arcaro, C. (C.), Baack, D. (D.), Babic, A. (A.), Banerjee, B. (B.), Bangale, P. (P.), Barres de Almeida, U. (U.), Barrio, J. A. (J. A.), Becerra Gonzalez, J. (J.), Bednarek, W. (W.), Bernardini, E. (E.), Berse, R. C. (R. Ch.), Berti, A. (A.), Bhattacharyya, W. (W.), Bigongiari, C. (C.), Biland, A. (A.), Blanch, O. (O.), Bonnoli, G. (G.), Carosi, R. (R.), Ceribella, G. (G.), Chatterjee, A. (A.), Colak, S. M. (S. M.), Colin, P. (P.), Colombo, E. (E.), Contreras, J. L. (J. L.), Cortina, J. (J.), Covino, S. (S.), Cumani, P. (P.), D'Elia, V. (V.), Da Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Ramazani, V. F. (V. Fallah), Fattorini, A. (A.), Fernandez-Barral, A. (A.), Ferrara, G. (G.), Fidalgo, D. (D.), Foffano, L. (L.), Fonseca, M. V. (M. V.), Font, L. (L.), Fruck, C. (C.), Galindo, D. (D.), Gallozzi, S. (S.), Garcia Lopez, R. J. (R. J.), Garczarczyk, M. (M.), Gaug, M. (M.), Giammaria, P. (P.), Godinovic, N. (N.), Gora, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), Hassan, T. (T.), Hayashida, M. (M.), Herrera, J. (J.), Hoang, J. (J.), Hose, J. (J.), Hrupec, D. (D.), Ishio, K. (K.), Konno, Y. (Y.), Kubo, H. (H.), Kushida, J. (J.), Lamastra, A. (A.), Lelas, D. (D.), Leone, F. (F.), Lindfors, E. (E.), Lombardi, S. (S.), Longo, F. (F.), Lopez, M. (M.), Maggio, C. (C.), Majumdar, P. (P.), Makariev, M. (M.), Maneva, G. (G.), Manganaro, M. (M.), Mannheim, K. (K.), Maraschi, L. (L.), Mariotti, M. (M.), Martinez, M. (M.), Masuda, S. (S.), Mazin, D. (D.), Mielke, K. (K.), Minev, M. (M.), Miranda, J. M. (J. M.), Mirzoyan, R. (R.), Moralejo, A. (A.), Moreno, V. (V.), Moretti, E. (E.), Nagayoshi, T. (T.), Neustroev, V. (V.), Niedzwiecki, A. (A.), Nievas Rosillo, M. (M.), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Paiano, S. (S.), Palacio, J. (J.), Paneque, D. (D.), Paoletti, R. (R.), Paredes, J. M. (J. M.), Pedaletti, G. (G.), Penil, P. (P.), Peresano, M. (M.), Persic, M. (M.), Pfrang, K. (K.), Moroni, P. G. (P. G. Prada), Prandini, E. (E.), Puljak, I. (I.), Garcia, J. R. (J. R.), Reichardt, I. (I.), Rhode, W. (W.), Ribo, M. (M.), Rico, J. (J.), Righi, C. (C.), Rugliancich, A. (A.), Saha, L. (L.), Saito, T. (T.), Satalecka, K. (K.), Schweizer, T. (T.), Sitarek, J. (J.), Snidaric, I. (I.), Sobczynska, D. (D.), Stamerra, A. (A.), Strzys, M. (M.), Suric, T. (T.), Takahashi, M. (M.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), Glawion, D. (D.), Takalo, L. O. (L. O.), and Jormanainen, J. (J.)

Abstract

We report on the detection of flaring activity from the Fanaroff-Riley I radio galaxy NGC 1275 in very-high-energy (VHE, E > 100 GeV) gamma rays with the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes. The observations were performed between 2016 September and 2017 February, as part of a monitoring programme. The brightest outburst, with ∼1.5 times the Crab Nebula flux above 100 GeV (C.U.), was observed during the night between 2016 December 31 and 2017 January 1. The flux is fifty times higher than the mean flux previously measured in two observational campaigns between 2009 October and 2010 February and between 2010 August and 2011 February. Significant variability of the day-by-day light curve was measured. The shortest flux-doubling timescale was found to be of (611 ± 101) min. The spectra calculated for this period are harder and show a significant curvature with respect to the ones obtained in the previous campaigns. The combined spectrum of the MAGIC data during the strongest flare state and simultaneous data from the Fermi-LAT around 2017 January 1 follows a power law with an exponential cutoff at the energy (492 ± 35) GeV. We further present simultaneous optical flux density measurements in the R-band obtained with the Kungliga Vetenskaps Akademien (KVA) telescope and investigate the correlation between the optical and gamma-ray emission. Due to possible internal pair-production, the fast flux variability constrains the Doppler factor to values that are inconsistent with a large viewing angle as observed in the radio band. We investigate different scenarios for the explanation of fast gamma-ray variability, namely emission from magnetospheric gaps, relativistic blobs propagating in the jet (mini-jets), or an external cloud (or star) entering the jet. We find that the only plausible model to account for the luminosities here observed would be the production of gamma rays in a magnetospheric gap around the central black hole, only in

Published
2018

17. Long-term study of Mkn 421 with the HAGAR Array of Telescopes

Author

Sinha, A., primary, Shukla, A., additional, Saha, L., additional, Acharya, B. S., additional, Anupama, G. C., additional, Bhattacharjee, P., additional, Britto, R. J., additional, Chitnis, V. R., additional, Prabhu, T. P., additional, Singh, B. B., additional, and Vishwanath, P. R., additional

Published
2016
Full Text
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20. 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

21. MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

Author

David Paneque, A. Biland, T. Schweizer, D. Ninci, Elina Lindfors, J. Besenrieder, D. Guberman, Masahiro Teshima, Chiara Righi, Daniel Mazin, A. De Angelis, J. Becerra González, A. Berti, S. Ansoldi, N. Godinović, S. Fukami, B. Machado de Oliveira Fraga, L. Bellizzi, Giacomo Bonnoli, D. Dominis Prester, K. Mannheim, N. Torres-Albà, J. Palacio, J. van Scherpenberg, P. Da Vela, A. Babić, D. Elsaesser, M. Ribó, D. Morcuende, P. Peñil, F. Leone, I. Šnidarić, A. Rugliancich, Marina Manganaro, V. Moreno, Dario Hrupec, Antonio Stamerra, P. G. Prada Moroni, G. Ceribella, Massimo Persic, Stefano Covino, Konstancja Satalecka, V. Fallah Ramazani, L. Nogués, P. Majumdar, Jose Carlos Herrera, Michele Doro, M. A. Lopez, G. Maneva, Elisa Prandini, D. Miceli, D. Fidalgo, Julian Sitarek, M. Mariotti, S. Cikota, M. I. Martínez, Razmik Mirzoyan, L. Saha, A. Chilingaryan, W. Rhode, G. Vanzo, M. Strzys, J. M. Paredes, Kyoshi Nishijima, U. Barres de Almeida, U. Colin, David A. Green, D. Hadasch, E. Do Souto Espiñeira, Tomislav Terzić, Ciro Bigongiari, D. Dorner, L. A. Antonelli, Petar Temnikov, M. Mallamaci, M. Minev, W. Bhattacharyya, Christian Fruck, S. Lombardi, D. Zarić, Jordi Delgado, John Hoang, Elisa Bernardini, G. Busetto, Y. Suda, Jose Luis Contreras, Dorota Sobczyńska, C. Maggio, Juan Cortina, R. López-Coto, Saša Mićanović, T. Surić, D. Lelas, Fabrizio Tavecchio, Y. Chai, Seiya Nozaki, S. Gasparyan, A. Lamastra, Eduardo Colombo, Ll. Font, S. M. Colak, D. Strom, J. Kushida, V. Vagelli, M. V. Fonseca, Auni Somero, M. Peresano, Kevin Schmidt, A. Arbet Engels, F. Di Pierro, M. Palatiello, Vitaly Neustroev, Luca Tosti, Juan Abel Barrio, M. Takahashi, I. Puljak, Narek Sahakyan, Carlo Vigorito, Laura Maraschi, Francesco Dazzi, Riccardo Paoletti, Markus Gaug, M. Vazquez Acosta, Nicola Giglietto, Valerio D'Elia, M. Delfino, A. López-Oramas, P. Munar-Adrover, G. Ferrara, Susumu Inoue, Abelardo Moralejo, E. Moretti, D. Depaoli, C. Nigro, V. A. Acciari, M. Makariev, Dominik Baack, R. J. García López, Luca Foffano, Francesco Giordano, Kari Nilsson, J. Rico, H. Kubo, Daniel Kerszberg, M. Will, Ž. Bošnjak, L. Jouvin, S. Loporchio, Simona Paiano, K. Noda, Jose Miguel Miranda, Edgar Molina, T. Saito, L. Di Venere, M. Hütten, B. Banerjee, Shunsuke Sakurai, Vincenzo Vitale, Ievgen Vovk, A. Hahn, Y. Iwamura, Markus Garczarczyk, Kazuma Ishio, B. De Lotto, W. Bednarek, Francesco Longo, Oscar Blanch, A. Fattorini, Roberto Carosi, Tomohiro Inada, A. Donini, Federal Ministry of Education and Research (Germany), Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Department of Atomic Energy (India), Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, Universidad de Barcelona, Croatian Science Foundation, University of Rijeka, Ministério da Ciência, Tecnologia e Inovação (Brasil), Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., 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., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., 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., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Micanovic, S., Miceli, D., 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., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, 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., Vagelli, V., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., and Zaric, D.

Subjects
Gamma rays: general, ISM: supernova remnants, Methods: observational, Astronomy, gamma rays general, methods observational, ISM supernova remnants, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, model [emission], generalI [Gamma rays], Astrophysics, 01 natural sciences, Raigs gamma, optical, MAGIC (telescope), 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Supernoves, supernova remnants [ISM], Astrophysics::Instrumentation and Methods for Astrophysics, imaging, Supernovae, Gamma rays: generalI, high [energy], Spectral energy distribution, Física nuclear, Astrophysics::High Energy Astrophysical Phenomena, general [Gamma rays], FOS: Physical sciences, SM: supernova remnants, monitoring [atmosphere], emission [gamma ray], 0103 physical sciences, Calibration, observational [Methods], 14. Life underwater, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Cherenkov radiation, Zenith, Computer Science::Information Retrieval, Gamma rays, Astronomy and Astrophysics, calibration, supernova remnants [SM], MAGIC, Cherenkov counter, Crab Nebula, Space and Planetary Science, ddc:520, spectral, supernova remnant [ISM], Energy (signal processing), Fermi Gamma-ray Space Telescope
Abstract

Aims. We measure the Crab Nebula γ-ray spectral energy distribution in the ~100 TeV energy domain and test the validity of existing leptonic emission models at these high energies. Methods. We used the novel very large zenith angle observations with the MAGIC telescope system to increase the collection area above 10 TeV. We also developed an auxiliary procedure of monitoring atmospheric transmission in order to assure proper calibration of the accumulated data. This employs recording optical images of the stellar field next to the source position, which provides a better than 10% accuracy for the transmission measurements. Results. We demonstrate that MAGIC very large zenith angle observations yield a collection area larger than a square kilometer. In only ~ 56 h of observations, we detect the γ-ray emission from the Crab Nebula up to 100 TeV, thus providing the highest energy measurement of this source to date with Imaging Atmospheric Cherenkov Telescopes. Comparing accumulated and archival MAGIC and Fermi/LAT data with some of the existing emission models, we find that none of them provides an accurate description of the 1 GeV to 100 TeV γ-ray signal., 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, FPA2017-90566-REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018 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 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. This research has made use of the CTA instrument response functions provided by the CTA Consortium and Observatory, see http://www.cta-observatory.org/science/cta-performance/ (version prod3b-v1) for more details.

Published
2020

22. MAGIC observations of the diffuse γ -ray emission in the vicinity of the Galactic center

Author

U. Barres de Almeida, L. Nogués, Damir Lelas, Dorota Sobczyńska, Daniel Kerszberg, Zeljka Bosnjak, Satoshi Masuda, L. Maraschi, Elina Lindfors, M. Peresano, B. Banerjee, D. Strom, A. Rugliancich, Marina Manganaro, D. Zarić, Daniel Mazin, D. Dominis Prester, Shunsuke Sakurai, Kyoshi Nishijima, D. Fidalgo, Marc Ribó, I. Snidaric, S. Paiano, Pratik Majumdar, M. V. Fonseca, Giacomo Bonnoli, Martin Will, Karl Mannheim, Ivica Puljak, Seiya Nozaki, Juan Abel Barrio, M. Nöthe, Narek Sahakyan, Toshiaki Inada, Hidetoshi Kubo, G. Busetto, Konstancja Satalecka, Michele Doro, E. Molina, Pablo Peñil, P. Munar-Adrover, E. Colombo, Saša Mićanović, John Hoang, V. Fallah Ramazani, Lab Saha, T. Schweizer, Luca Foffano, K. Noda, Daniel Morcuende, Jose Luis Contreras, M. Palatiello, V. Vitale, J. Becerra González, Juan Cortina, Stefano Covino, Francesco Dazzi, A. Fernández-Barral, Alice Donini, L. A. Antonelli, D. Ninci, Sanae Inoue, U. Colin, Manuela Mallamaci, D. Hadasch, Alessio Berti, Kai Phillip Schmidt, Sidika Merve Colak, David A. Green, Alexander Hahn, Wrijupan Bhattacharyya, Jordi Delgado, Tomoki Saito, Giovanni Ceribella, J. van Scherpenberg, A. Arbet Engels, Léa Jouvin, Sargis Gasparyan, Fabrizio Tavecchio, A. Somero, F. Di Pierro, Lluis Font, Stefano Ansoldi, Manuel Delfino, I. Vovk, B. Machado de Oliveira Fraga, Vitaly Neustroev, Davide Depaoli, Riccardo Paoletti, Wolfgang Rhode, M. Strzys, David Paneque, D. Miceli, Mosè Mariotti, Yuki Iwamura, A. López-Oramas, P. G. Prada Moroni, N. Giglietto, Valerio Vagelli, Chiara Righi, G. Ferrara, J. Palacio, D. Guberman, Ana Babić, Nikola Godinovic, Luca Tosti, Ferdinando Giordano, P. Temnikov, Alicia Fattorini, R. J. García López, J. M. Paredes, Antonio Stamerra, Junko Kushida, P. Da Vela, M. I. Martínez, Serena Loporchio, Satoshi Fukami, G. Maneva, Jürgen Besenrieder, Christian Fruck, Camilla Maggio, Daniela Dorner, D. Elsaesser, Gaia Vanzo, V. A. Acciari, Massimo Persic, F. Leone, V. D'Elia, Kari Nilsson, M. Gaug, Adrian Biland, Masahiro Teshima, Saverio Lombardi, J. Herrera, Julian Sitarek, Cosimo Nigro, Elisa Bernardini, J. Rico, Dario Hrupec, M. A. Lopez, Mitsunari Takahashi, A. Chilingaryan, Dominik Baack, E. Do Souto Espiñeira, Tomislav Terzić, A. De Angelis, Yusuke Suda, Carlo Vigorito, Moritz Hütten, Abelardo Moralejo, E. Moretti, M. Minev, B. De Lotto, Ciro Bigongiari, M. Garczarczyk, R. López-Coto, Kazuma Ishio, Elisa Prandini, Rodolfo Carosi, R. Mirzoyan, Yating Chai, Stefan Cikota, M. Vazquez Acosta, Victoria Moreno, Francesco Longo, Lorenzo Bellizzi, Martin Makariev, Oscar Blanch, T. Surić, Shimpei Tsujimoto, Wlodek Bednarek, N. Torres-Albà, Jose Miguel Miranda, Alessandra Lamastra, L. Di Venere, Federal Ministry of Education and Research (Germany), Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, Universidad de Barcelona, Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, Ministério da Ciência e Tecnologia (Brasil), Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., 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., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., 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., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Micanovic, S., Miceli, D., 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., Nothe, M., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, 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., Tsujimoto, S., Vagelli, V., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., and Zaric, D.

Subjects
model [background], accelerator, Point source, Astrophysics::High Energy Astrophysical Phenomena, Gamma rays: general, background: model, general [Gamma rays], Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, programming, 01 natural sciences, Spectral line, law.invention, energy: threshold, law, gas, TRACER, 0103 physical sciences, ISM [Gamma rays], 010306 general physics, 010303 astronomy & astrophysics, Cosmic rays, Zenith, Astrophysics::Galaxy Astrophysics, Physics, Gamma rays: ISM, Galaxy: center, Galactic ridge, Galactic Center, Astronomy and Astrophysics, Particle accelerator, center [Galaxy], threshold [energy], MAGIC, gamma ray, Space and Planetary Science, cosmic radiation: galaxy, ddc:520, galaxy [cosmic radiation], Física nuclear, gamma rays: general, gamma rays: ISM, cosmic rays, Astrophysics - High Energy Astrophysical Phenomena
Abstract

[Aims] In the presence of a sufficient amount of target material, γ-rays can be used as a tracer in the search for sources of Galactic cosmic rays (CRs). Here we present deep observations of the Galactic center (GC) region with the MAGIC telescopes and use them to infer the underlying CR distribution and to study the alleged PeV proton accelerator at the center of our Galaxy., [Methods] We used data from ≈100 h observations of the GC region conducted with the MAGIC telescopes over five years (from 2012 to 2017). Those were collected at high zenith angles (58−70 deg), leading to a larger energy threshold, but also an increased effective collection area compared to low zenith observations. Using recently developed software tools, we derived the instrument response and background models required for extracting the diffuse emission in the region. We used existing measurements of the gas distribution in the GC region to derive the underlying distribution of CRs. We present a discussion of the associated biases and limitations of such an approach., [Results] We obtain a significant detection for all four model components used to fit our data (Sgr A*, “Arc”, G0.9+0.1, and an extended component for the Galactic Ridge). We observe no significant difference between the γ-ray spectra of the immediate GC surroundings, which we model as a point source (Sgr A*) and the Galactic Ridge. The latter can be described as a power-law with index 2 and an exponential cut-off at around 20 TeV with the significance of the cut-off being only 2σ. The derived cosmic-ray profile hints to a peak at the GC position and with a measured profile index of 1.2 ± 0.3 is consistent with the 1/r radial distance scaling law, which supports the hypothesis of a CR accelerator at the GC. We argue that the measurements of this profile are presently limited by our knowledge of the gas distribution in the GC vicinity., 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, FPA2017-90566-REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT, the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018 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 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 Center grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ.

Published
2020

23. Study of the variable broadband emission of Markarian 501 during the most extreme Swift X-ray activity

Author

Francesco Longo, Yuki Iwamura, Susumu Inoue, L. Nogués, M. I. Martínez, G. Pedaletti, Thomas Bretz, J. Buss, A. Rugliancich, Marina Manganaro, D. Galindo, Merja Tornikoski, Sabrina Einecke, Martin Makariev, Oscar Blanch, C. Leto, Ciro Bigongiari, Adrian Biland, D. Zarić, Andrii Neronov, M. Garczarczyk, Sargis Gasparyan, Konstancja Satalecka, Michele Doro, Marc Ribó, M. Noethe, J. Becerra González, Kazuma Ishio, J. Rico, Christian Fruck, Kyoshi Nishijima, Abelardo Moralejo, E. Moretti, Wolfgang Rhode, Christoph Wendel, Dominik Baack, Satoshi Masuda, Hidetoshi Kubo, Nikola Godinovic, B. Machado de Oliveira Fraga, Alexander Hahn, Manuel Delfino, Daniela Dorner, P. Giammaria, A. Niedzwiecki, Alessio Berti, U. Barres de Almeida, F. Verrecchia, G. Busetto, Lena Linhoff, D. Fidalgo, Damir Lelas, G. Ferrara, Alicia Fattorini, D. Hildebrand, David Paneque, V. A. Acciari, Bernd Schleicher, Gaia Vanzo, M. Peresano, Rodolfo Carosi, M. Perri, Alessandra Lamastra, John Hoang, Marcel Strzys, M. Gaug, Chiara Righi, M. Armas Padilla, D. Ninci, Ana Babić, Michael Blank, Dorota Sobczyńska, D. Dominis Prester, A. De Angelis, Vitaly Neustroev, I. Snidaric, F. Schulz, E. von Willert, D. Guberman, A. Y. Lien, J. Herrera, Juan Abel Barrio, B. Banerjee, J. van Scherpenberg, V. D'Elia, Narek Sahakyan, P. Temnikov, Stefano Ansoldi, R. J. García López, G. Maneva, E. Do Souto Espiñera, B. De Lotto, Elisa Bernardini, Riccardo Paoletti, S. Paiano, Karl Mannheim, Pablo Peñil, A. Shukla, Ivica Puljak, Jose Luis Contreras, D. Neise, Andrea Tramacere, Manuela Mallamaci, A. López-Oramas, Jordi Delgado, V. Fallah Ramazani, Juan Cortina, J. Palacio, P. Colin, R. Walter, J. M. Paredes, F. Di Pierro, Antonio Stamerra, Pratik Majumdar, Camilla Maggio, M. V. Fonseca, Ievgen Vovk, Francesco Dazzi, A. Fernández-Barral, Cosimo Nigro, P. Munar-Adrover, Massimo Persic, Dario Hrupec, L. A. Antonelli, Martin Will, D. Kuveždić, T. Schweizer, F. Leone, Anne Lähteenmäki, Tarek M. Hassan, Fabrizio Tavecchio, Masahiro Teshima, A. Somero, Kari Nilsson, Ll. Font, M. Bulinski, Wlodek Bednarek, Vitalii Sliusar, P. G. Prada Moroni, Junko Kushida, P. Da Vela, E. Prandini, N. Torres-Albà, Joni Tammi, Sebastian Achim Mueller, J. R. Garcia, Giacomo Bonnoli, Manuel Doerr, Stefano Gallozzi, Jose Miguel Miranda, Wrijupan Bhattacharyya, Julian Sitarek, T. Surić, Shimpei Tsujimoto, K. Bruegge, D. Elsaesser, Tomislav Terzić, Jürgen Besenrieder, E. Molina, E. Colombo, Lab Saha, Luca Foffano, Mosè Mariotti, A. Paravac, Saverio Lombardi, M. Nievas Rosillo, M. Minev, M. Balbo, D. Hadasch, R. Mirzoyan, A. Arbet-Engels, K. Sedlaczek, L. Maraschi, Elina Lindfors, Daniel Mazin, Stefan Cikota, M. Vazquez Acosta, Victoria Moreno, Stefano Covino, Tomoki Saito, Giovanni Ceribella, Aaron Dominguez, K. Noda, Sidika Merve Colak, M. López, German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Croatian Science Foundation, University of Rijeka, Polish National Agency for Academic Exchange, Ministério da Ciência, Tecnologia e Inovação (Brasil), National Aeronautics and Space Administration (US), Department of Energy (US), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Centre National de la Recherche Scientifique (France), Institut National de Physique Nucléaire et de Physique des Particules (France), Agenzia Spaziale Italiana, High Energy Accelerator Research Organization (Japan), Japan Aerospace Exploration Agency, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish National Space Board, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bonnoli, G., Busetto, 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 Espinera, E., Dominguez, A., Dominis Prester, D., Doro, M., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Gallozzi, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giammaria, P., Godinovic, 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., Kuvecdic, D., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Oramas, A., MacHado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martinez, 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., Nogues, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strzys, M., Suric, T., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zaric, D., Arbet-Engels, A., Baack, D., Balbo, M., Biland, A., Blank, M., Bretz, T., Bruegge, K., Bulinski, M., Buss, J., Doerr, M., Dorner, D., Einecke, S., Elsaesser, D., Hildebrand, D., Linhoff, L., Mannheim, K., Mueller, S., Neise, D., Neronov, A., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Schulz, F., Sedlaczek, K., Shukla, A., Sliusar, V., Von Willert, E., Walter, R., Wendel, C., Tramacere, A., Lien, A., Perri, M., Verrecchia, F., Armas Padilla, M., Leto, C., Lahteenmaki, A., Tornikoski, M., Tammi, J., Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, and Aalto University

Subjects
galaxies: active, BL Lacertae objects: individual: Mrk 501, gamma rays: galaxies, X-rays: galaxies, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Power law, Spectral line, Galaxies: active, Gamma rays: galaxies, individual: Mrk 501 [BL Lacertae objects], 0103 physical sciences, MAGIC (telescope), Blazar, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, galaxie [Gamma rays], 010308 nuclear & particles physics, Gamma ray, Astronomy and Astrophysics, galaxies [X-rays], Crab Nebula, Space and Planetary Science, active [galaxies], galaxies [gamma rays], ddc:520, Física nuclear, High Energy Astrophysical Phenomena, Astrophysics - High Energy Astrophysical Phenomena
Abstract

[Context] Markarian 501 (Mrk 501) is a very high-energy (VHE) gamma-ray blazar located at z = 0:034, which is regularly monitored by a wide range of multi-wavelength instruments, from radio to VHE gamma rays. During a period of almost two weeks in July 2014, the highest X-ray activity of Mrk 501 was observed in -14 years of operation of the Neil Gehrels Swift Gamma-ray Burst Observatory., [Aims] We characterize the broadband variability of Mrk 501 from radio to VHE gamma rays during the most extreme X-ray activity measured in the last 14 years, and evaluate whether it can be interpreted within theoretical scenarios widely used to explain the broadband emission from blazars., [Methods] The emission of Mrk 501 was measured at radio with Metsähovi, at optical–UV with KVA and Swift/UVOT, at X-ray with Swift/XRT and Swift/BAT, at gamma ray with Fermi-LAT, and at VHE gamma rays with the FACT and MAGIC telescopes. The multi-band variability and correlations were quantified, and the broadband spectral energy distributions (SEDs) were compared with predictions from theoretical models., [Results] The VHE emission of Mrk 501 was found to be elevated during the X-ray outburst, with a gamma-ray flux above 0.15 TeV varying from ∼0.5 to ∼2 times the Crab nebula flux. The X-ray and VHE emission both varied on timescales of 1 day and were found to be correlated. We measured a general increase in the fractional variability with energy, with the VHE variability being twice as large as the X-ray variability. The temporal evolution of the most prominent and variable segments of the SED, characterized on a day-by-day basis from 2014 July 16 to 2014 July 31, is described with a one-zone synchrotron self-Compton model with variations in the break energy of the electron energy distribution (EED), and with some adjustments in the magnetic field strength and spectral shape of the EED. These results suggest that the main flux variations during this extreme X-ray outburst are produced by the acceleration and the cooling of the high-energy electrons. A narrow feature at ∼3 TeV was observed in the VHE spectrum measured on 2014 July 19 (MJD 56857.98), which is the day with the highest X-ray flux (>0.3 keV) measured during the entire Swift mission. This feature is inconsistent with the classical analytic functions to describe the measured VHE spectra (power law, log-parabola, and log-parabola with exponential cutoff) at more than 3σ. A fit with a log-parabola plus a narrow component is preferred over the fit with a single log-parabola at more than 4σ, and a dedicated Monte Carlo simulation estimated the significance of this extra component to be larger than 3σ. Under the assumption that this VHE spectral feature is real, we show that it can be reproduced with three distinct theoretical scenarios: (a) a pileup in the EED due to stochastic acceleration; (b) a structured jet with two-SSC emitting regions, with one region dominated by an extremely narrow EED; and (c) an emission from an IC pair cascade induced by electrons accelerated in a magnetospheric vacuum gap, in addition to the SSC emission from a more conventional region along the jet of Mrk 501., 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, FPA2017-90566-REDC), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 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. 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 Instituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. 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 (Ver-bundforschung 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, project C3. We thank the Instituto de Astrofisica de Canarias for allowing us to operate the telescope at the Observatorio del Roque de los Muchachos in La Palma, the Max-Planck-Institut fur Physik for providing us with the mount of the former HEGRA CT3 telescope, and the MAGIC Collaboration for their support. JBG acknowledges the support of the Viera y Clavijo program funded by ACIISI and ULL. C. W. is grateful for the support by the project “Promotion inklusive” of the Universität zu Köln and the German Bundesmin-isterium für Arbeit und Soziales. This publication makes use of data obtained at Metsähovi Radio Observatory, operated by Aalto University, Finland.

Published
2020

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