Time-dependent modelling of short-term variability in the TeV-blazar VER J0521+211 during the major flare in 2020
Creators: name: MAGIC Collaboration
name: Abe, S.
name: Abhir, J.
name: Abhishek, A.
name: Acciari, V. A.
name: Aguasca-Cabot, A.
name: Agudo, I.
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: de Almeida, U. Barres
name: Barrio, J. A.
name: Batković, I.
name: Bautista, A.
name: Baxter, J.
name: González, J. Becerra
name: Bednarek, W.
name: Bernardini, E.
name: Bernete, J.
name: Berti, A.
name: Besenrieder, J.
name: Bigongiari, C.
name: Biland, A.
name: Blanch, O.
name: Bonnoli, G.
name: Bošnjak, Ž.
name: Bronzini, E.
name: Burelli, I.
name: Campoy-Ordaz, A.
name: Carosi, A.
name: Carosi, R.
name: Carretero-Castrillo, M.
name: Castro-Tirado, A. J.
name: Cerasole, D.
name: Ceribella, G.
name: Chai, Y.
name: Cifuentes, A.
name: Colombo, E.
name: Contreras, J. L.
name: Cortina, J.
name: Covino, S.
name: D'Amico, G.
name: D'Elia, V.
name: Da Vela, P.
name: Dazzi, F.
name: De Angelis, A.
name: De Lotto, B.
name: de Menezes, R.
name: Delfino, M.
name: Delgado, J.
name: Mendez, C. Delgado
name: Di Pierro, F.
name: Di Tria, R.
name: Di Venere, L.
name: Prester, D. Dominis
name: Donini, A.
name: Dorner, D.
name: Doro, M.
name: Eisenberger, L.
name: Elsaesser, D.
name: Escudero, J.
name: Fariña, L.
name: Fattorini, A.
name: Foffano, L.
name: Font, L.
name: Fröse, S.
name: Fukami, S.
name: Fukazawa, Y.
name: López, R. J. García
name: Garczarczyk, M.
name: Gasparyan, S.
name: Gaug, M.
name: Paiva, J. G. Giesbrecht
name: Giglietto, N.
name: Giordano, F.
name: Gliwny, P.
name: Gradetzke, T.
name: Grau, R.
name: Green, D.
name: Green, J. G.
name: Günther, P.
name: Hadasch, D.
name: Hahn, A.
name: Hassan, T.
name: Heckmann, L.
name: Llorente, J. Herrera
name: Hrupec, D.
name: Imazawa, R.
name: Ishio, K.
name: Martínez, I. Jiménez
name: Jormanainen, J.
name: Kankkunen, S.
name: Kayanoki, T.
name: Kerszberg, D.
name: Kluge, G. W.
name: Kobayashi, Y.
name: Kouch, P. M.
name: Kubo, H.
name: Kushida, J.
name: Láinez, M.
name: Lamastra, A.
name: Leone, F.
name: Lindfors, E.
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: Lyard, E.
name: Fraga, B. Machado de Oliveira
name: Majumdar, P.
name: Makariev, M.
name: Maneva, G.
name: Manganaro, M.
name: Mangano, S.
name: Mannheim, K.
name: Mariotti, M.
name: Martínez, M.
name: Martínez-Chicharro, M.
name: Mas-Aguilar, A.
name: Mazin, D.
name: Menchiari, S.
name: Mender, S.
name: Miceli, D.
name: Miener, T.
name: Miranda, J. M.
name: Mirzoyan, R.
name: González, M. Molero
name: Molina, E.
name: Mondal, H. A.
name: Moralejo, A.
name: Morcuende, D.
name: Nakamori, T.
name: Nanci, C.
name: Neustroev, V.
name: Nickel, L.
name: Rosillo, M. Nievas
name: Nigro, C.
name: Nikolić, L.
name: Nilsson, K.
name: Nishijima, K.
name: Ekoume, T. Njoh
name: Noda, K.
name: Nozaki, S.
name: Ohtani, Y.
name: Okumura, A.
name: Otero-Santos, J.
name: Paiano, S.
name: Paneque, D.
name: Paoletti, R.
name: Paredes, J. M.
name: Peresano, M.
name: Persic, M.
name: Pihet, M.
name: Pirola, G.
name: Podobnik, F.
name: Moroni, P. G. Prada
name: Prandini, E.
name: Principe, G.
name: Rhode, W.
name: Ribó, M.
name: Rico, J.
name: Righi, C.
name: Sahakyan, N.
name: Saito, T.
name: Saturni, F. G.
name: Schmidt, K.
name: Schmuckermaier, F.
name: Schubert, J. L.
name: Schweizer, T.
name: Sciaccaluga, A.
name: Silvestri, G.
name: Sitarek, J.
name: Sliusar, V.
name: Sobczynska, D.
name: Spolon, A.
name: Stamerra, A.
name: Strišković, J.
name: Strom, D.
name: Strzys, M.
name: Suda, Y.
name: Tajima, H.
name: Takahashi, M.
name: Takeishi, R.
name: Temnikov, P.
name: Terauchi, K.
name: Terzić, T.
name: Teshima, M.
name: Truzzi, S.
name: Tutone, A.
name: Ubach, S.
name: van Scherpenberg, J.
name: Acosta, M. Vazquez
name: Ventura, S.
name: Verna, G.
name: Viale, I.
name: Vigorito, C. F.
name: Vitale, V.
name: Vovk, I.
name: Walter, R.
name: Wersig, F.
name: Will, M.
name: Wunderlich, C.
name: Yamamoto, T.
name: collaborators, MWL
name: :
name: Bachev, R.
name: Ramazani, V. Fallah
name: Filippenko, A. V.
name: Hovatta, T.
name: Jorstad, S. G.
name: Kiehlmann, S.
name: Lähteenmäki, A.
name: Liodakis, I.
name: Marscher, A. P.
name: Max-Moerbeck, W.
name: Omeliukh, A.
name: Pursimo, T.
name: Readhead, A. C. S.
name: Rodrigues, X.
name: Tornikoski, M.
name: Wierda, F.
name: Zheng, W.
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The BL Lacertae object VER J0521+211 underwent a notable flaring episode in February 2020. A short-term monitoring campaign, led by the MAGIC (Major Atmospheric Gamma Imaging Cherenkov) collaboration, covering a wide energy range from radio to very-high-energy (VHE, 100 GeV &lt; E &lt; 100 TeV) gamma rays was organised to study its evolution. These observations resulted in a consistent detection of the source over six consecutive nights in the VHE gamma-ray domain. Combining these nightly observations with an extensive set of multiwavelength data made modelling of the blazar's spectral energy distribution (SED) possible during the flare. This modelling was performed with a focus on two plausible emission mechanisms: i) a leptonic two-zone synchrotron-self-Compton scenario, and ii) a lepto-hadronic one-zone scenario. Both models effectively replicated the observed SED from radio to the VHE gamma-ray band. Furthermore, by introducing a set of evolving parameters, both models were successful in reproducing the evolution of the fluxes measured in different bands throughout the observing campaign. Notably, the lepto-hadronic model predicts enhanced photon and neutrino fluxes at ultra-high energies (E &gt; 100 TeV). While the photon component, generated via decay of neutral pions, is not directly observable as it is subject to intense pair production (and therefore extinction) through interactions with the cosmic microwave background photons, neutrino detectors (e.g. IceCube) can probe the predicted neutrino component. Finally, the analysis of the gamma-ray spectra, as observed by MAGIC and the Fermi-LAT telescopes, yielded a conservative 95\% confidence upper limit of z \leq 0.244 for the redshift of this blazar.
description: Accepted for publication in A&amp;A