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1. Multiwavelength study of the gravitationally lensed blazar QSO B0218+357 between 2016 and 2020

Author

V A Acciari, S Ansoldi, L A Antonelli, A Arbet Engels, M Artero, K Asano, D Baack, A Babić, A Baquero, U Barres de Almeida, J A Barrio, I Batković, J Becerra González, W Bednarek, L Bellizzi, E Bernardini, M Bernardos, A Berti, J Besenrieder, W Bhattacharyya, C Bigongiari, A Biland, O Blanch, G Bonnoli, Ž Bošnjak, G Busetto, R Carosi, G Ceribella, M Cerruti, Y Chai, A Chilingarian, S Cikota, S M Colak, E Colombo, J L Contreras, J Cortina, S Covino, G D’Amico, V D’Elia, P Da Vela, F Dazzi, A De Angelis, B De Lotto, M Delfino, J Delgado, C Delgado Mendez, D Depaoli, F Di Pierro, L Di Venere, E Do Souto Espiñeira, D Dominis Prester, A Donini, D Dorner, M Doro, D Elsaesser, V Fallah Ramazani, A Fattorini, G Ferrara, M V Fonseca, L Font, C Fruck, S Fukami, R J García López, M Garczarczyk, S Gasparyan, M Gaug, N Giglietto, F Giordano, P Gliwny, N Godinović, J G Green, D Green, D Hadasch, A Hahn, L Heckmann, J Herrera, J Hoang, D Hrupec, M Hütten, T Inada, S Inoue, K Ishio, Y Iwamura, I Jiménez, J Jormanainen, L Jouvin, Y Kajiwara, M Karjalainen, D Kerszberg, Y Kobayashi, H Kubo, J Kushida, A Lamastra, D Lelas, F Leone, E Lindfors, S Lombardi, F Longo, R López-Coto, M López-Moya, A López-Oramas, S Loporchio, B Machado de Oliveira Fraga, C Maggio, P Majumdar, M Makariev, M Mallamaci, G Maneva, M Manganaro, K Mannheim, L Maraschi, M Mariotti, M Martínez, D Mazin, S Menchiari, S Mender, S Mićanović, D Miceli, T Miener, M Minev, J M Miranda, R Mirzoyan, E Molina, A Moralejo, D Morcuende, V Moreno, E Moretti, V Neustroev, C Nigro, K Nilsson, K Nishijima, K Noda, S Nozaki, Y Ohtani, T Oka, J Otero-Santos, S Paiano, M Palatiello, D Paneque, R Paoletti, J M Paredes, L Pavletić, P Peñil, C Perennes, M Persic, P G Prada Moroni, E Prandini, C Priyadarshi, I Puljak, W Rhode, M Ribó, J Rico, C Righi, A Rugliancich, L Saha, N Sahakyan, T Saito, S Sakurai, K Satalecka, F G Saturni, B Schleicher, K Schmidt, T Schweizer, J Sitarek, I Šnidarić, D Sobczynska, A Spolon, A Stamerra, D Strom, M Strzys, Y Suda, T Surić, M Takahashi, F Tavecchio, P Temnikov, T Terzić, M Teshima, L Tosti, S Truzzi, A Tutone, S Ubach, J van Scherpenberg, G Vanzo, M Vazquez Acosta, S Ventura, V Verguilov, C F Vigorito, V Vitale, I Vovk, M Will, C Wunderlich, D Zarić, F de Palma, F D’Ammando, A Barnacka, D K Sahu, M Hodges, T Hovatta, S Kiehlmann, W Max-Moerbeck, A C S Readhead, R Reeves, T J Pearson, A Lähteenmäki, I Björklund, M Tornikoski, J Tammi, S Suutarinen, K Hada, and K Niinuma

Published
2021
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2. Multiwavelength Variability and Correlation Studies of Mrk 421 During Historically Low X-ray and Y-ray Activity in 2015–2016

Author

Janeth Valverde Quispe, V. A. Acciari, S. Ansoldi, L. A. Antonelli, K. Asano, A. Babic, B. Banerjee, A. Baquero, U.BarresdeAlmeida, J. A. Barrio, J. Becerra Gonzalez, W. Bednarek, L. Bellizzi, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, O. Blanch, G. Bonnoli, Z. Bosnjak, G. Busetto, R. Carosi, G. Ceribella, M. Cerruti, Y. Chai, A. Chilingarian, S. Cikota, S. M. Colak, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, T. Di Girolamo, F. Di Pierro, L. Di Venere, E. Do Souto Espineira, D. Dominis Prester, A. Donini, M. Doro, V. Fallah Ramazani, A. Fattorini, G. Ferrara, L. Foffano, M. V. Fonseca, L. Font, C. Fruck, S. Fukami, R. J. Garcıa Lopez, M. Garczarczyk, S. Gasparyan, M. Gaug, N. Giglietto, F. Giordano, P. Gliwny, N. Godinovic, J. G. Green, D. Green, D. Hadasch, A. Hahn, L. Heckmann, J. Herrera, J. Hoang, D. Hrupec, M. Hutten, T. Inada, S. Inoue, K. Ishio, Y. Iwamura, J. Jormanainen, L. Jouvin, Y. Kajiwara, M. Karjalainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, S. Lombardi, F. Longo, M. Lopez, R. Lopez-Coto, A. Lopez-Oramas, S. Loporchio, B. Machado de Oliveira Fraga, C. Maggio, P. Majumdar, M. Makariev, M. Mallamaci, G. Maneva, M. Manganaro, L. Maraschi, M. Mariotti, M. Martınez, D. Mazin, S. Mender, S. Micanovic, D. Miceli, T. Miener, M. Minev, J. M. Miranda, R. Mirzoyan, E. Molina, A. Moralejo, D. Morcuende, V. Moreno, E. Moretti, P. Munar-Adrover, V. Neustroev, C. Nigro, K. Nilsson, D. Ninci, K. Nishijima, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, J. Otero-Santos, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletic, P. P enil, C. Perennes, M. Persic, P. G . Prada Moroni, E. Prandini, C. Priyadarshi, I. Puljak, W. Rhode, M. Ribo, J. Rico, C. Righi, A. Rugliancich, L. Saha, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, B. Schleicher, K. Schmidt, T. Schweizer, J. Sitarek, I. Snidaric, D. Sobczynska, A. Spolon, A. Stamerra, D. Strom, M. Strzys, Y. Suda, T. Suric, M. Takahashi, F. Tavecchio, P. Temnikov, T. Terzic, M. Teshima, N. Torres-Alba, L. Tosti, S. Truzzi, J. van Scherpenberg, G. Vanzo, M. Vazquez Acosta, S. Ventura, V. Verguilov, C. F. Vigorito, V. Vitale, I. Vovk, M. Will, D. Zaric, A. Arbet-Engels, D. Baack, M. Balbo, M. Beck, N. Biederbeck, A. Biland, T. Bretz, K. Bruegge, J. Buss, D. Dorner, D. Elsaesser, D. Hildebrand, R. Iotov, M. Klinger, K. Mannheim, D. Neise, A. Neronov, M. Noethe, A. Paravac, V. Sliusar, F. Theissen, R. Walter, J. Valverde, D. Horan, M. Giroletti, M. Perri, F. Verrecchia, C. Leto, A. C. Sadun, J. W. Moody, M. Joner, A. P. Marscher, S. G. Jorstad, A. Lahteenmaki, M. Tornikoski, V. Ramakrishnan, E. Jarvela, R. J. C. Vera, S. Righini, and A.Y.Lien

Subjects
Astronomy
Abstract

We report a characterization of the multiband flux variability and correlations of the nearby (z=0.031) blazar Markarian 421(Mrk 421) using data from Mets ̈ahovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1TeV<1.7×10−12ph cm−2s−1) and in the 2–10 keV (X-ray) band (F2−10 keV<3.6×10−11erg cm−2s−1),during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E>0.1 TeV)γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our dataset with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9−6d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process.

Published
2020
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3. Observation of inverse Compton emission from a long γ-ray burst

Author

P. Veres, P. N. Bhat, M. S. Briggs, W. H. Cleveland, R. Hamburg, C. M. Hui, B. Mailyan, R. D. Preece, O. J. Roberts, A. von Kienlin, C. A. Wilson-Hodge, D. Kocevski, M. Arimoto, D. Tak, K. Asano, M. Axelsson, G. Barbiellini, E. Bissaldi, F.Fana Dirirsa, R. Gill, J. Granot, J. McEnery, N. Omodei, S. Razzaque, F. Piron, J. L. Racusin, D. J. Thompson, S. Campana, M. G. Bernardini, N. P. M. Kuin, M. H. Siegel, S. B. Cenko, P. O’Brien, M. Capalbi, A. Daì, M. De Pasquale, J. Gropp, N. Klingler, J. P. Osborne, M. Perri, R. L. C. Starling, G. Tagliaferri, A. Tohuvavohu, A. Ursi, M.Tavani, M. Cardillo, C. Casentini, G. Piano, Y. Evangelista, F. Verrecchia, C. Pittori, F. Lucarelli, A. Bulgarelli, N. Parmiggiani, G. E. Anderson, J. P. Anderson, G. Bernardi, J. Bolmer, M. D. Caballero-García, I. M. Carrasco, A. Castellón, N. Castro Segura, A. J. Castro-Tirado, S. V. Cherukuri, A. M. Cockeram, P. D’Avanzo, A. Di Dato, R. Diretse, R. P. Fender, E. Fernández-García, J. P. U. Fynbo, A. S.Fruchter, J. Greiner, M. Gromadzki, K. E. Heintz, I. Heywood, A. J. van der Horst, Y.-D. Hu, C. Inserra, L. Izzo, V. Jaiswal, P. Jakobsson, J. Japelj, E. Kankare, D. A.Kann, C. Kouveliotou, S. Klose, A. J. Levan, X. Y. Li, S. Lotti, K. Maguire, D. B. Malesani, I. Manulis, M. Marongiu, S. Martin, A. Melandri, M. J.Michałowski, J. C. A. Miller-Jones, K. Misra, A. Moin, K. P. Mooley, S. Nasri, M. Nicholl, A. Noschese, G. Novara, S. B. Pandey, E. Peretti, C. J. Pérez del Pulgar, M. A. Pérez-Torres, D. A. Perley, L. Piro, F. Ragosta, L. Resmi, R. Ricci, A. Rossi, R. Sánchez-Ramírez, J. Selsing, S. Schulze, S. J. Smartt, I. A. Smith, V. V. Sokolov, J. Stevens, N. R. Tanvir, C. C. Thöne, A. Tiengo, E. Tremou, E. Troja, A. de Ugarte Postigo, A. F. Valeev, S. D. Vergani, M. Wieringa, P. A. Woudt, D. Xu, O. Yaron, D. R. Young, V. A. Acciari, S. Ansoldi, L. A. Antonelli, A. Arbet Engels, D. Baack, A. Babić, B. Banerjee, U. Barres de Almeida, J. A. Barrio, J. Becerra González, W. Bednarek, L. Bellizzi, E. Bernardini, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, G. Busetto, R. Carosi, G. Ceribella, Y. Chai, A. Chilingaryan, S. Cikota, S. M. Colak, U. Colin, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, M. Delfino, J. Delgado, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, V. Fallah Ramazani, A. Fattorini, G. Ferrara, D. Fidalgo, L. Foffano, M. V. Fonseca, L. Font, C. Fruck, S. Fukami, R. J. García López, M. Garczarczyk, S.Gasparyan, M. Gaug, N. Giglietto, F. Giordano, N. Godinović, D. Green, D. Guberman, D. Hadasch, A. Hahn, J. Herrera, J. Hoang, D. Hrupec, M. Hütten, T. Inada, S. Inoue, K. Ishio, Y. Iwamura, L. Jouvin, D. Kerszberg, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, S. Lombardi, F. Longo, M. López, R. López-Coto, A. López-Oramas, S. Loporchio, B. Machado de Oliveira Fraga, C. Maggio, P. Majumdar, M. Makariev, M. Mallamaci, G. Maneva, M. Manganaro, K. Mannheim, L. Maraschi, M. Mariotti, M. Martínez, D. Mazin, S. Mićanović, D. Miceli, M. Minev, J. M. Miranda, R. Mirzoyan, E. Molina, A. Moralejo, D. Morcuende, V. Moreno, E. Moretti, P. Munar-Adrover, V. Neustroev, C. Nigro, K. Nilsson, D. Ninci, K. Nishijima, K. Noda, L. Nogués, S. Nozaki, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, P. Peñil, M. Peresano, M. Persic, P. G. Prada Moroni, E. Prandini, I. Puljak, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, L. Saha, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, K. Schmidt, T. Schweizer, J. Sitarek, I. Šnidarić, D. Sobczynska, A. Somero, A. Stamerra, D. Strom, M. Strzys, Y. Suda, T. Surić, M. Takahashi, F. Tavecchio, P. Temnikov, T. Terzić, M. Teshima, N. Torres-Albà, L. Tosti, V. Vagelli, J. van Scherpenberg, G. Vanzo, M. Vazquez Acosta, C. F. Vigorito, V. Vitale, I. Vovk, M. Will, D. Zarić, and L. Nava

Subjects
Space Sciences (General)
Abstract

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C. Here we report multifrequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10^(−6) to 10^(12) electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

Published
2019
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4. Possible Evidence for Free Precession of a Strongly Magnetized Neutron Star in the Magnetar 4U 0142+61

Author

K Makishima, T Enoto, J S Hiraga, T Nakano, K Nakazawa, S Sakurai, M Sasano, and H Murakami

Subjects
Astrophysics
Abstract

Magnetars are a special type of neutron stars, considered to have extreme dipole magnetic fields reaching approximately 10(exp 11) T. The magnetar 4U 0142þ61, one of the prototypes of this class, was studied in broadband x rays (0.5-70 keV) with the Suzaku observatory. In hard x rays (15-40 keV), its 8.69 sec pulsations suffered slow phase modulations by +/- 0.7 sec, with a period of approximately 15 h. When this effect is interpreted as free precession of the neutron star, the object is inferred to deviate from spherical symmetry by approximately 1.6 x 10(epx -4) in its moments of inertia. This deformation, when ascribed to magnetic pressure, suggest a strong toroidal magnetic field, approximately 10(exp 12) T, residing inside the object. This provides one of the first observational approaches towards toroidal magnetic fields of magnetars.

Published
2014
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