MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

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

In: Monthly Notices of the Royal Astronomical Society, 2015, vol. 451, no. 1, p. 739-750

Add to personal list
    Summary
    The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z=0.138) was discovered in very high energy (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 Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) observations yielded a γ-ray signal above 250GeV of (3.7±0.7)percent of the Crab Nebula flux with a statistical significance of 9.9σ. 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±0.29 between ∼150GeV and 1TeV and an integral flux of (9.3±1.9)percent of the Crab nebula flux above 250GeV. 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