MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524
Creators: name: MAGIC Collaboration
name: Aleksić, J.
name: Ansoldi, S.
name: Antonelli, L. A.
name: Antoranz, P.
name: Babic, A.
name: Bangale, P.
name: Barrio, J. A.
name: González, J. Becerra
name: Bednarek, W.
name: Bernardini, E.
name: Biasuzzi, B.
name: Biland, A.
name: Blanch, O.
name: Bonnefoy, S.
name: Bonnoli, G.
name: Borracci, F.
name: Bretz, T.
name: Carmona, E.
name: Carosi, A.
name: Colin, P.
name: Colombo, E.
name: Contreras, J. L.
name: Cortina, J.
name: Covino, S.
name: Da Vela, P.
name: Dazzi, F.
name: De Angelis, A.
name: De Caneva, G.
name: De Lotto, B.
name: Wilhelmi, E. de O. na
name: Mendez, C. Delgado
name: Di Pierro, F.
name: Prester, D. Dominis
name: Dorner, D.
name: Doro, M.
name: Einecke, S.
name: Eisenacher, D.
name: Elsaesser, D.
name: Fernández-Barral, A.
name: Fidalgo, D.
name: Fonseca, M. V.
name: Font, L.
name: Frantzen, K.
name: Fruck, C.
name: Galindo, D.
name: López, R. J. García
name: Garczarczyk, M.
name: Terrats, D. Garrido
name: Gaug, M.
name: Godinović, N.
name: noz, A. González Mu.
name: Gozzini, S. R.
name: Hadasch, D.
name: Hanabata, Y.
name: Hayashida, M.
name: Herrera, J.
name: Hose, J.
name: Hrupec, D.
name: Idec, W.
name: Kadenius, V.
name: Kellermann, H.
name: Knoetig, M. L.
name: Kodani, K.
name: Konno, Y.
name: Krause, J.
name: Kubo, H.
name: Kushida, J.
name: La Barbera, A.
name: Lelas, D.
name: Lewandowska, N.
name: Lindfors, E.
name: Lombardi, S.
name: Longo, F.
name: López, M.
name: López-Coto, R.
name: López-Oramas, A.
name: Lorenz, E.
name: Lozano, I.
name: Makariev, M.
name: Mallot, K.
name: Maneva, G.
name: Mannheim, K.
name: Maraschi, L.
name: Marcote, B.
name: Mariotti, M.
name: Martínez, M.
name: Mazin, D.
name: Menzel, U.
name: Miranda, J. M.
name: Mirzoyan, R.
name: Moralejo, A.
name: Munar-Adrover, P.
name: Nakajima, D.
name: Neustroev, V.
name: Niedzwiecki, A.
name: Rosillo, M. Nievas
name: Nilsson, K.
name: Nishijima, K.
name: Noda, K.
name: Orito, R.
name: Overkemping, A.
name: Paiano, S.
name: Palatiello, M.
name: Paneque, D.
name: Paoletti, R.
name: Paredes, J. M.
name: Paredes-Fortuny, X.
name: Persic, M.
name: Poutanen, J.
name: Moroni, P. G. Prada
name: Prandini, E.
name: Puljak, I.
name: Reinthal, R.
name: Rhode, W.
name: Ribó, M.
name: Rico, J.
name: Garcia, J. Rodriguez
name: Saito, T.
name: Saito, K.
name: Satalecka, K.
name: Scalzotto, V.
name: Scapin, V.
name: Schultz, C.
name: Schweizer, T.
name: Shore, S. N.
name: Sillanpää, A.
name: Sitarek, J.
name: Snidaric, I.
name: Sobczynska, D.
name: Stamerra, A.
name: Steinbring, T.
name: Strzys, M.
name: Takalo, L.
name: Takami, H.
name: Tavecchio, F.
name: Temnikov, P.
name: Terzić, T.
name: Tescaro, D.
name: Teshima, M.
name: Thaele, J.
name: Torres, D. F.
name: Toyama, T.
name: Treves, A.
name: Vogler, P.
name: Will, M.
name: Zanin, R.
name: Berger, K.
name: Buson, S.
name: D'Ammando, F.
name: Gasparrini, D.
name: Hovatta, T.
name: Max-Moerbeck, W.
name: Readhead, A.
name: Richards, J.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in VHE $γ$ rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed multiwavelength observations from $γ$ rays to radio performed from 2011 January to March, which were triggered by the high activity detected at optical frequencies. These observations constitute the most precise determination of the broad-band emission of 1ES 0806+524 to date. The stereoscopic MAGIC observations yielded a $γ$-ray signal above 250 GeV of $(3.7 \pm 0.7)$ per cent of the Crab Nebula flux with a statistical significance of 9.9 $σ$. The multiwavelength observations showed significant variability in essentially all energy bands, including a VHE $γ$-ray flare that lasted less than one night, which provided unprecedented evidence for short-term variability in 1ES 0806+524. The spectrum of this flare is well described by a power law with a photon index of $2.97 \pm 0.29$ between $\sim$150 GeV and 1 TeV and an integral flux of $(9.3 \pm 1.9)$ per cent of the Crab Nebula flux above 250 GeV. The spectrum during the non-flaring VHE activity is compatible with the only available VHE observation performed in 2008 with VERITAS when the source was in a low optical state. The broad-band spectral energy distribution can be described with a one-zone Synchrotron Self Compton model with parameters typical for HBLs, indicating that 1ES 0806+524 is not substantially different from the HBLs previously detected.
description: 12 pages, 8 figures, 3 tables, accepted 2015 April 20 for publication in Monthly Notices of the Royal Astronomical Society Main Journal