Multiwavelength Observations of the Blazar VER J0521+211 during an Elevated TeV Gamma-Ray State
Creators: name: Adams, C. B.
name: Batista, P.
name: Benbow, W.
name: Brill, A.
name: Brose, R.
name: Buckley, J. H.
name: Capasso, M.
name: Christiansen, J. L.
name: Errando, M.
name: Feng, Q.
name: Finley, J. P.
name: Foote, G. M.
name: Fortson, L.
name: Furniss, A.
name: Gallagher, G.
name: Gent, A.
name: Giuri, Chiara
name: Hanlon, W. F.
name: Hanna, D.
name: Hassan Collado, Tarek
name: Hervet, O.
name: Holder, J.
name: Hona, B.
name: Hughes, G.
name: Humensky, T. B.
name: Jin, W.
name: Kaaret, P.
name: Kertzman, M.
name: Kieda, D.
name: Kleiner, Tobias Kai
name: Krennrich, F.
name: Kumar, S.
name: Lang, M. J.
name: Lundy, M.
name: Maier, G.
name: Millis, J.
name: Moriarty, P.
name: Mukherjee, R.
name: Nievas-Rosillo, M.
name: O’Brien, S.
name: Ong, R. A.
name: Otte, A. N.
name: Patel, Sonal Ramesh
name: Patel, S. R.
name: Pfrang, Konstantin Johannes
name: Pohl, M.
name: Prado, R. R.
name: Pueschel, E.
name: Quinn, J.
name: Ragan, K.
name: Reynolds, P. T.
name: Ribeiro, D.
name: Roache, E.
name: Ryan, J. L.
name: Sadeh, I.
name: Santander, M.
name: Sembroski, G. H.
name: Shang, R.
name: Stevenson, B.
name: Tucci, J. V.
name: Vassiliev, V. V.
name: Wakely, S. P.
name: Weinstein, A.
name: Wells, R. M.
name: Williams, D. A.
name: Williamson, T. J.
name: Acciari, V. A.
name: Aniello, T.
name: Ansoldi, S.
name: Antonelli, L. A.
name: Engels, A. Arbet
name: Arcaro, C.
name: Artero, M.
name: Asano, K.
name: Baack, D.
name: Babić, A.
name: Baquero, A.
name: de Almeida, U. Barres
name: Barrio, J. A.
name: Batković, I.
name: González, J. Becerra
name: Bednarek, W.
name: Bernardini, E.
name: Bernardos, M.
name: Berti, A.
name: Besenrieder, J.
name: Bhattacharyya, W.
name: Bigongiari, C.
name: Biland, A.
name: Blanch, O.
name: Bökenkamp, H.
name: Bonnoli, G.
name: Bošnjak, Ž.
name: Burelli, I.
name: Busetto, G.
name: Carosi, R.
name: Ceribella, G.
name: Cerruti, M.
name: Chai, Y.
name: Chilingarian, A.
name: Cikota, S.
name: Colombo, E.
name: Contreras, J. L.
name: Cortina, J.
name: Covino, S.
name: D’Amico, G.
name: D’Elia, V.
name: Vela, P. Da
name: Dazzi, F.
name: Angelis, A. De
name: Lotto, B. De
name: Popolo, A. Del
name: Delfino, M.
name: Delgado, J.
name: Mendez, C. Delgado
name: Depaoli, D.
name: Pierro, F. Di
name: Venere, L. Di
name: Souto Espiñeira, E. Do
name: Prester, D. Dominis
name: Donini, A.
name: Dorner, D.
name: Doro, M.
name: Elsaesser, D.
name: Ramazani, V. Fallah
name: Fariña, L.
name: Fattorini, A.
name: Font, L.
name: Fruck, C.
name: Fukami, S.
name: Fukazawa, Y.
name: López, R. J. García
name: Garczarczyk, M.
name: Gasparyan, S.
name: Gaug, M.
name: Giglietto, N.
name: Giordano, F.
name: Gliwny, P.
name: Godinović, N.
name: Green, J. G.
name: Green, D.
name: Hadasch, D.
name: Hahn, A.
name: Hassan, T.
name: Heckmann, L.
name: Herrera, J.
name: Hrupec, D.
name: Hütten, M.
name: Inada, T.
name: Iotov, R.
name: Ishio, K.
name: Iwamura, Y.
name: Martínez, I. Jiménez
name: Jormanainen, J.
name: Jouvin, L.
name: Kerszberg, D.
name: Kobayashi, Y.
name: Kubo, H.
name: Kushida, J.
name: Lamastra, A.
name: Lelas, D.
name: Leone, F.
name: Lindfors, E.
name: Linhoff, L.
name: Lombardi, S.
name: Longo, F.
name: López-Coto, R.
name: López-Moya, M.
name: López-Oramas, A.
name: Loporchio, S.
name: Lorini, A.
name: de Oliveira Fraga, B. Machado
name: Maggio, C.
name: Majumdar, P.
name: Makariev, M.
name: Maneva, G.
name: Manganaro, M.
name: Mannheim, K.
name: Mariotti, M.
name: Martínez, M.
name: Aguilar, A. Mas
name: Mazin, D.
name: Menchiari, S.
name: Mender, S.
name: Mićanović, S.
name: Miceli, D.
name: Miener, T.
name: Miranda, J. M.
name: Mirzoyan, R.
name: Molina, E.
name: Mondal, H. A.
name: Moralejo, A.
name: Morcuende, D.
name: Moreno, V.
name: Nakamori, T.
name: Nanci, C.
name: Nava, L.
name: Neustroev, V.
name: Rosillo, M. Nievas
name: Nigro, C.
name: Nilsson, K.
name: Nishijima, K.
name: Noda, K.
name: Nozaki, S.
name: Ohtani, Y.
name: Oka, T.
name: Otero-Santos, J.
name: Paiano, S.
name: Palatiello, M.
name: Paneque, D.
name: Paoletti, R.
name: Paredes, J. M.
name: Pavletić, L.
name: Peñil, P.
name: Persic, M.
name: Pihet, M.
name: Prada Moroni, P. G.
name: Prandini, E.
name: Priyadarshi, C.
name: Puljak, I.
name: Rhode, W.
name: Ribó, M.
name: Rico, J.
name: Righi, C.
name: Rugliancich, A.
name: Sahakyan, N.
name: Saito, T.
name: Sakurai, S.
name: Satalecka, K.
name: Saturni, F. G.
name: Schleicher, B.
name: Schmidt, K.
name: Schmuckermaier, F.
name: Schubert, J. L.
name: Schweizer, T.
name: Sitarek, J.
name: Šnidarić, I.
name: Sobczynska, D.
name: Spolon, A.
name: Stamerra, A.
name: Strišković, J.
name: Strom, D.
name: Strzys, M.
name: Suda, Y.
name: Surić, T.
name: Takahashi, M.
name: Takeishi, R.
name: Tavecchio, F.
name: Temnikov, P.
name: Terzić, T.
name: Teshima, M.
name: Tosti, L.
name: Truzzi, S.
name: Tutone, A.
name: Ubach, S.
name: van Scherpenberg, J.
name: Vanzo, G.
name: Acosta, M. Vazquez
name: Ventura, S.
name: Verguilov, V.
name: Viale, I.
name: Vigorito, C. F.
name: Vitale, V.
name: Vovk, I.
name: Will, M.
name: Wunderlich, C.
name: Yamamoto, T.
name: Zarić, D.
name: VERITAS Collaboration
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2022
Subjects: subject: 520

description: We report on a long-lasting, elevated gamma-ray flux state from VER J0521+211 observed by VERITAS, MAGIC, and Fermi-LAT in 2013 and 2014. The peak integral flux above 200 GeV measured with the nightly binned light curve is (8.8 ± 0.4) × 10$^{−7}$ photons m$^{−2}$ s$^{−1}$, or ∼37% of the Crab Nebula flux. Multiwavelength observations from X-ray, UV, and optical instruments are also presented. A moderate correlation between the X-ray and TeV gamma-ray fluxes was observed, and the X-ray spectrum appeared harder when the flux was higher. Using the gamma-ray spectrum and four models of the extragalactic background light (EBL), a conservative 95% confidence upper limit on the redshift of the source was found to be z ≤ 0.31. Unlike the gamma-ray and X-ray bands, the optical flux did not increase significantly during the studied period compared to the archival low-state flux. The spectral variability from optical to X-ray bands suggests that the synchrotron peak of the spectral energy distribution (SED) may become broader during flaring states, which can be adequately described with a one-zone synchrotron self-Compton model varying the high-energy end of the underlying particle spectrum. The synchrotron peak frequency of the SED and the radio morphology of the jet from the MOJAVE program are consistent with the source being an intermediate-frequency-peaked BL Lac object.