PoS - Proceedings of Science
Volume 444 - 38th International Cosmic Ray Conference (ICRC2023) - Gamma-ray Astronomy (GA)
Long-term study of the intermittent extreme behaviour of 1ES 2344+514
W. Zheng, A. Filippenko, A. Arbet-Engels*, C. Leto, C. Raiteri, R. Chatterjee, F. Verrechia, M. Perri, M. Villata, S. Das,  The MAGIC Collaboration, H. Abe, S. Abe, J. Abhir, V.A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L.A. Antonelli, A. Arbet Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J.A. Barrio, I. Batković, J.R. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M.I. Bernardos, J. Bernete, A. Berti, J. Besenrieder, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Z. Bosnjak, I. Burelli, G. Busetto, A. Campoy-Ordaz, A. Carosi, R. Carosi, M. Carretero-Castrillo, A.J. Castro-Tirado, G. Ceribella, Y. Chai, A.A. Chilingarian, A. Cifuentes, S. Cikota, 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, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, L. Fariña, A. Fattorini, L. Foffano, L. Font, S. Fröse, S. Fukami, Y. Fukazawa, R.J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J.G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau Haro, D. Green, J.G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, G.W. Kluge, Y. Kobayashi, P.M. Kouch, H. Kubo, J. Kushida, M. Láinez Lezáun, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, É. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, M. Martínez-Chicharro, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J.M. Miranda, R. Mirzoyan, M. Molero Gonzalez, E. Molina, H.A. Mondal, A. Moralejo, D. Morcuende, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, L. Nickel, M. Nievas Rosillo, C. Nigro, L. Nikolić, K. Nilsson, K. Nishijima, T.R. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J.M. Paredes, L. Pavletić, D. Pavlović, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P.G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F.G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J.L. Schubert, T. Schweizer, A. Sciaccaluga, J. Sitarek, V. Sliusar, D. Sobczyńska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M.C. Strzys, Y. Suda, T. Surić, S. Suutarinen, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C.f. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto and F. D'Ammandoet al. (click to show)
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Pre-published on: August 08, 2023
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Extreme high-frequency-peaked BL Lac objects (EHBLs) are the most energetic persistent sources in the universe. They are characterized by a spectral energy distribution (SED) featuring a synchrotron peak energy above 1 keV. 1ES 2344+514 is a blazar known to behave as an EHBL intermittently. Until now, its EHBL nature was only reported during flares, but a coherent picture is missing as unbiased monitoring campaigns are lacking. This work presents the longest observing campaign from radio to very-high-energy (VHE) frequencies performed so far on 1ES2344+514. Using observations from between 2019-2021, we carry out a systematic investigation of the intermittent EHBL phases. The dataset also includes X-ray observations from NuSTAR, XMM-Newton, and AstroSAT together with MAGIC, providing an unprecedented determination of the two SED components.
For the first time we report a clear EHBL behaviour during a low flux activity in 1ES 2344+514. It implies a significant hardening of the electron distribution inside the jet independent of flux. We also detect a bright X-ray state characterized by an unusually soft spectra, thus violating the harder-when-brighter relation typically found in blazars. The spectral study further reveals an excess in the ultraviolet data with respect to the extrapolation of the X-ray spectrum, suggesting at least two regions contributing to the synchrotron flux. Finally we investigate a gamma-ray flare not accompanied by an X-ray counterpart. This peculiar outburst is interpreted using a time-dependent model involving two emitting components.
DOI: https://doi.org/10.22323/1.444.0788
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