A1 Refereed original research article in a scientific journal
An intermittent extreme BL Lac: MWL study of 1ES 2344+514 in an enhanced state
Authors: V A Acciari, S Ansoldi, L A Antonelli, A Arbet Engels, 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, O Blanch, G Bonnoli, Ž Bošnjak, G Busetto, R Carosi, G Ceribella, M Cerruti, 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, M Doro, D Elsaesser, V Fallah Ramazani, A Fattorini, G Ferrara, 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, P Gliwny, D Green, D Hadasch, A Hahn, J Herrera, J Hoang, D Hrupec, M Hütten, T Inada, S Inoue, K Ishio, Y Iwamura, L Jouvin, Y Kajiwara, D Kerszberg, Y Kobayashi, 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, L Maraschi, M Mariotti, M Martínez, D Mazin, 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, P Munar-Adrover, V Neustroev, C Nigro, K Nilsson, D Ninci, K Nishijima, K Noda, L Nogués, S Nozaki, Y Ohtani, T Oka, J Otero-Santos, S Paiano, M Palatiello, D Paneque, R Paoletti, J M Paredes, L Pavletić, P Peñil, M Peresano, M Persic, P G Prada Moroni, E Prandini, I Puljak, M Ribó, 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 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, N Torres-Albà, L Tosti, J van Scherpenberg, G Vanzo, M Vazquez Acosta, S Ventura, V Verguilov, C F Vigorito, V Vitale, I Vovk, M Will, D Zarić, FACT Collaboration: D Baack, M Balbo, M Beck, N Biederbeck, A Biland, M Blank, T Bretz, K Bruegge, M Bulinski, J Buss, M Doerr, D Dorner, D Hildebrand, R Iotov, M Klinger, K Mannheim, S Achim Mueller, D Neise, A Neronov, M Nöthe, A Paravac, W Rhode, B Schleicher, K Sedlaczek, A Shukla, V Sliusar, L Tani, F Theissen, R Walter, MWL Collaborators: J Acosta Pulido, A V Filippenko, T Hovatta, S Kiehlmann, V M Larionov, W Max-Moerbeck, C M Raiteri, A C S Readhead, M Šegon, M Villata, W Zheng
Publisher: OXFORD UNIV PRESS
Publication year: 2020
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 496
Issue: 3
First page : 3912
Last page: 3928
Number of pages: 17
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/staa1702
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/50724156
Extreme high-frequency BL Lacs (EHBL) feature their synchrotron peak of the broad-band spectral energy distribution (SED) at nu(s) >= 10(17) Hz. The BL Lac object 1ES 2344+514 was included in the EHBL family because of its impressive shift of the synchrotron peak in 1996. During the following years, the source appeared to be in a low state without showing any extreme behaviours. In 2016 August, 1ES 2344+514 was detected with the groundbased gamma-ray telescope FACT during a high gamma-ray state, triggering multiwavelength (MWL) observations. We studied the MWL light curves of 1ES 2344+514 during the 2016 flaring state, using data from radio to very-high-energy (VHE) gamma-rays taken with OVRO, KAIT, KVA, NOT, some telescopes of the GASP-WEBT collaboration at the Teide, Crimean, and St. Petersburg observatories, Swift-UVOT, Swift-XRT, Fermi-LAT, FACT, and MAGIC. With simultaneous observations of the flare, we built the broad-band SED and studied it in the framework of a leptonic and a hadronic model. The VHE gamma-ray observations show a flux level of 55 per cent of the Crab Nebula flux above 300 GeV, similar to the historical maximum of 1995. The combination of MAGIC and Fermi-LAT spectra provides an unprecedented characterization of the inverse-Compton peak for this object during a flaring episode. The Gamma index of the intrinsic spectrum in the VHE gamma-ray band is 2.04 +/- 0.12(stat) +/- 0.15(sys). We find the source in an extreme state with a shift of the position of the synchrotron peak to frequencies above or equal to 1018 Hz.
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