E-resources
PDF-
Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Arcaro, C.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Buson, S.; Carosi, A.; Colin, P.; Contreras, J. L.; Cortina, J.; Da Vela, P.; De Lotto, B.; Di Pierro, F.; Doert, M.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garrido Terrats, D.; Gaug, M.; Gora, D.; Guberman, D.; Herrera, J.; Hose, J.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lindfors, E.; Longo, F.; López, M.; López-Coto, R.; Majumdar, P.; Makariev, M.; Maneva, G.; Mannheim, K.; Mirzoyan, R.; Nakajima, D.; Neustroev, V.; Nishijima, K.; Noda, K.; Nogués, L.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prandini, E.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Snidaric, I.; Sobczynska, D.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Terzić, T.; Tescaro, D.; Teshima, M.; Toyama, T.; Vanzo, G.; Verguilov, V.; Vovk, I.; Will, M.; Wu, M. H.
Astronomy and astrophysics (Berlin), 11/2016, Volume: 595Journal Article
Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components that are spatially indistinguishable by gamma-ray instruments, but separated by a 10–12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. Aims. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma-ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. Methods. MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. Results. Very high energy gamma-ray emission was detected from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. The observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.
