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1. 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

2. The Great Markarian 421 flare of 2010 February:multiwavelength variability and correlation studies

Author: Abeysekara, A. U. (A. U.), Benbow, W. (W.), Bird, R. (R.), Brill, A. (A.), Brose, R. (R.), Buchovecky, M. (M.), Buckley, J. H. (J. H.), Christiansen, J. L. (J. L.), Chromey, A. J. (A. J.), Daniel, M. K. (M. K.), Dumm, J. (J.), Falcone, A. (A.), Feng, Q. (Q.), Finley, J. P. (J. P.), Fortson, L. (L.), Furniss, A. (A.), Galante, N. (N.), Gent, A. (A.), Gillanders, G. H. (G. H.), Giuri, C. (C.), Gueta, O. (O.), Hassan, T. (T.), Hervet, O. (O.), Holder, J. (J.), Hughes, G. (G.), Humensky, T. B. (T. B.), Johnson, C. A. (C. A.), Kaaret, P. (P.), Kar, P. (P.), Kelley-Hoskins, N. (N.), Kertzman, M. (M.), Kieda, D. (D.), Krause, M. (M.), Krennrich, F. (F.), Kumar, S. (S.), Lang, M. J. (M. J.), Moriarty, P. (P.), Mukherjee, R. (R.), Nelson, T. (T.), Nieto, D. (D.), Nievas-Rosillo, M. (M.), O'Brien, S. (S.), Ong, R. A. (R. A.), Otte, A. N. (A. N.), Park, N. (N.), Petrashyk, A. (A.), Pichel, A. (A.), Pohl, M. (M.), Prado, R. R. (R. R.), Pueschel, E. (E.), Quinn, J. (J.), Ragan, K. (K.), Reynolds, P. T. (P. T.), Richards, G. T. (G. T.), Roache, E. (E.), Rovero, A. C. (A. C.), Rulten, C. (C.), Sadeh, I. (I), Santander, M. (M.), Sembroski, G. H. (G. H.), Shahinyan, K. (K.), Stevenson, B. (B.), Sushch, I. (I), Tyler, J. (J.), Vassiliev, V. V. (V. V.), Wakely, S. P. (S. P.), Weinstein, A. (A.), Wells, R. M. (R. M.), Wilcox, P. (P.), Wilhelm, A. (A.), Williams, D. A. (D. A.), Zitzer, B. (B.), 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.), 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), Vela, P. (P.), Dazzi, F. (F.), De Angelis, A. (A.), De Lotto, B. (B.), Delfino, M. (M.), Delgado, J. (J.), Di Pierro, F. (F.), Souto Espinera, E. (E.), 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.), 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.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, 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.), 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.), 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.), 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.), 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.), 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.), Sun, S. (S.), 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.), Aller, H. D. (H. D.), Aller, M. F. (M. F.), Carini, M. T. (M. T.), Horan, D. (D.), Jordan, B. (B.), Jorstad, S. G. (S. G.), Kurtanidze, O. M. (O. M.), Kurtanidze, S. O. (S. O.), Lahteenmaki, A. (A.), Larionov, V. M. (V. M.), Larionova, E. G. (E. G.), Madejski, G. (G.), Marscher, A. P. (A. P.), Max-Moerbeck, W. (W.), Moody, J. W. (J. Ward), Morozova, D. A. (D. A.), Nikolashvili, M. G. (M. G.), Raiteri, C. M. (C. M.), Readhead, A. C. (A. C. S.), Richards, J. L. (J. L.), Sadun, A. C. (A. C.), Sakamoto, T. (T.), Sigua, L. A. (L. A.), Smith, P. S. (P. S.), Talvikki, H. (H.), Tammi, J. (J.), Tornikoski, M. (M.), Troitsky, I. S. (I. S.), and Villata, M. (M.)
Subjects: Gamma-ray astronomy, Astrophysics::High Energy Astrophysical Phenomena, Time domain astronomy, BL Lacertae objects, Markarian galaxies, Relativistic jets, High energy astrophysics, Blazars
Abstract: We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ~27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsähovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare “decline“ epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ~25–55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ≳ 33) and the size of the emission region (δ⁻¹ RB ≲ × 10¹³ cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux–flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model.
Published: 2020

3. 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

4. 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

5. Discovery of TeV γ-ray emission from the neighbourhood of the supernova remnant G24.7+0.6 by MAGIC

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.), 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.), 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.), 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.), 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.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), de Ona Wilhelmi, E. (E.), Torres, D. F. (D. F.), Zanin, R. (R.), 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.), 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.), 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.), 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.), 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.), Vanzo, G. (G.), Vazquez Acosta, M. (M.), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), de Ona Wilhelmi, E. (E.), Torres, D. F. (D. F.), and Zanin, R. (R.)
Abstract: SNR G24.7+0.6 is a 9.5 kyrs radio and γ-ray supernova remnant evolving in a dense medium. In the GeV regime, SNR G24.7+0.6 (3FHL J1834.1–0706e/FGES J1834.1–0706) shows a hard spectral index (Γ ∼ 2) up to 200 GeV, which makes it a good candidate to be observed with Cherenkov telescopes such as MAGIC. We observed the field of view of SNR G24.7+0.6 with the MAGIC telescopes for a total of 31 h. We detect very high-energy γ-ray emission from an extended source located 0.34° away from the centre of the radio SNR. The new source, named MAGIC J1835–069 is detected up to 5 TeV, and its spectrum is well-represented by a power-law function with spectral index of 2.74 ± 0.08. The complexity of the region makes the identification of the origin of the very high-energy emission difficult; however, the spectral agreement with the LAT source and overlapping position at less than 1.5σ point to a common origin. We analysed 8 yr of Fermi-LAT data to extend the spectrum of the source down to 60 MeV. Fermi-LAT and MAGIC spectra overlap within errors and the global broad-band spectrum is described by a power law with exponential cut-off at 1.9 ± 0.5 TeV. The detected γ-ray emission can be interpreted as the results of proton–proton interaction between the supernova and the CO-rich surrounding.
Published: 2019

6. Measurement of the extragalactic background light using MAGIC and Fermi-LAT gamma-ray observations of blazars up to z = 1

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.), 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.), Chai, Y. (Y.), Cikota, S. (S.), Colak, M. (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.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), 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.), Galindo, D. (D.), Gallozzi, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Godinovic, N. (N.), Green, D. (D.), 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.), 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.), Rosillo, M. N. (M. Nievas), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), 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.), 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.), 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.), Acosta, M. V. (M. Vazquez), 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.), 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.), Chai, Y. (Y.), Cikota, S. (S.), Colak, M. (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.), Dominguez, A. (A.), Prester, D. D. (D. Dominis), 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.), Galindo, D. (D.), Gallozzi, S. (S.), Lopez, R. J. (R. J. Garcia), Garczarczyk, M. (M.), Gasparyan, S. (S.), Gaug, M. (M.), Godinovic, N. (N.), Green, D. (D.), 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.), 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.), Rosillo, M. N. (M. Nievas), Nigro, C. (C.), Nilsson, K. (K.), Ninci, D. (D.), Nishijima, K. (K.), Noda, K. (K.), Nogues, L. (L.), Nothe, M. (M.), 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.), 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.), 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.), Acosta, M. V. (M. Vazquez), Vovk, I. (I.), Will, M. (M.), and Zaric, D. (D.)
Abstract: We present a measurement of the extragalactic background light (EBL) based on a joint likelihood analysis of 32 gamma-ray spectra for 12 blazars in the redshift range z = 0.03–0.944, obtained by the MAGIC telescopes and Fermi-LAT. The EBL is the part of the diffuse extragalactic radiation spanning the ultraviolet, visible, and infrared bands. Major contributors to the EBL are the light emitted by stars through the history of the Universe, and the fraction of it that was absorbed by dust in galaxies and re-emitted at longer wavelengths. The EBL can be studied indirectly through its effect on very high energy photons that are emitted by cosmic sources and absorbed via γγ interactions during their propagation across cosmological distances. We obtain estimates of the EBL density in good agreement with state-of-the-art models of the EBL production and evolution. The 1σ upper bounds, including systematic uncertainties, are between 13 per cent and 23 per cent above the nominal EBL density in the models. No anomaly in the expected transparency of the Universe to gamma-rays is observed in any range of optical depth. We also perform a wavelength-resolved EBL determination, which results in a hint of an excess of EBL in the 0.18–0.62 μm range relative to the studied models, yet compatible with them within systematics.
Published: 2019

7. 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

8. Deep observations of the globular cluster M15 with the MAGIC telescopes

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.), 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.), 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.), Dominis Prester, D. (D.), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Fallah Ramazani, V. (V.), 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.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), 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.), 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.), Nothe, 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.), Prada Moroni, P. G. (P. G.), 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.), 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.), 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.), 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.), 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.), Dominis Prester, D. (D.), Dorner, D. (D.), Doro, M. (M.), Einecke, S. (S.), Elsaesser, D. (D.), Fallah Ramazani, V. (V.), 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.), Green, D. (D.), Guberman, D. (D.), Hadasch, D. (D.), Hahn, A. (A.), 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.), 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.), Nothe, 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.), Prada Moroni, P. G. (P. G.), 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.), 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.), and Zaric, D. (D.)
Abstract: A population of globular clusters (GCs) has been recently established by the Fermi-LAT telescope as a new class of GeV γ-ray sources. Leptons accelerated to TeV energies, in the inner magnetospheres of MSPs or in their wind regions, should produce γ-rays through the inverse Compton scattering in the dense radiation field from the huge population of stars. We have conducted deep observations of the GC M15 with the MAGIC telescopes and used 165 h in order to search for γ-ray emission. A strong upper limit on the TeV γ-ray flux < 3.2×10−13cm−2s−1 above 300 GeV (⁠<0.26 per cent of the Crab nebula flux) has been obtained. We interpret this limit as a constraint on the efficiency of the acceleration of leptons in the magnetospheres of the MSPs. We constrain the injection rate of relativistic leptons, ηe, from the MSPs magnetospheres and their surrounding. We conclude that ηe must be lower than expected from the modelling of high-energy processes in MSP inner magnetospheres. For leptons accelerated with the power-law spectrum in the MSP wind regions, ηe is constrained to be much lower than derived for the wind regions around classical pulsars. These constraints are valid for the expected range of magnetic field strengths within the GC and for the range of likely energies of leptons injected from the inner magnetospheres, provided that the leptons are not removed from the GC very efficiently due to advection process. We discuss consequences of these constraints for the models of radiation processes around millisecond pulsars.
Published: 2019

9. 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

10. The blazar TXS 0506+056 associated with a high-energy neutrino:insights into extragalactic jets and cosmic-ray acceleration

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.), Besenrieder, J. (J.), 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.), 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.), Hayashida, M. (M.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), 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.), 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.), 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.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), Cerruti, M. (Matteo), 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.), Besenrieder, J. (J.), 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.), 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.), Hayashida, M. (M.), Herrera, J. (J.), Hoang, J. (J.), Hrupec, D. (D.), Inoue, S. (S.), Ishio, K. (K.), Iwamura, Y. (Y.), 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.), 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.), 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.), Tavecchio, F. (F.), Temnikov, P. (P.), Terzic, T. (T.), Teshima, M. (M.), Torres-Alba, N. (N.), Tsujimoto, S. (S.), Vanzo, G. (G.), Acosta, M. V. (M. Vazquez), Vovk, I. (I.), Ward, J. E. (J. E.), Will, M. (M.), Zaric, D. (D.), and Cerruti, M. (Matteo)
Abstract: A neutrino with energy ~290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at ~3σ level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ~41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of ~10⁴⁵ – 4 × 10⁴⁶erg s⁻¹. The steep spectrum observed by MAGIC is concordant with internal γγ absorption above ~100 GeV entailed by photohadronic production of a ~290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range ~10¹⁴ – 10¹⁸ eV.
Published: 2018

11. 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

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11 results on '"Gallozzi, S. (S.)"'

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

2. The Great Markarian 421 flare of 2010 February:multiwavelength variability and correlation studies

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

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

5. Discovery of TeV γ-ray emission from the neighbourhood of the supernova remnant G24.7+0.6 by MAGIC

6. Measurement of the extragalactic background light using MAGIC and Fermi-LAT gamma-ray observations of blazars up to z = 1

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

8. Deep observations of the globular cluster M15 with the MAGIC telescopes

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

10. The blazar TXS 0506+056 associated with a high-energy neutrino:insights into extragalactic jets and cosmic-ray acceleration

11. Gamma-ray flaring activity of NGC1275 in 2016–2017 measured by MAGIC

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