Spectral Energy Distribution of Markarian 501: Quiescent State Versus Extreme Outburst

• Published in: The Astrophysical journal Vol. 729; no. 1; pp. 2 - jQuery1323910501317='48'
• Main Authors: Acciari, V. A, Arlen, T, Aune, T, Boltuch, D, Bradbury, S. M, Buckley, J. H, Bugaev, V, Ciupik, L, Dickherber, R, Duke, C, Errando, M, Falcone, A, Furniss, A, Hanna, D, Holder, J, Huang, D, Hui, C. M, Imran, A, Karlsson, N, Kertzman, M, Konopelko, A, McArthur, S, McCann, A, Pandel, D, Reyes, L. C, Rose, H. J, Sembroski, G. H, Swordy, S. P, Thibadeau, S, Vincent, S, Wakely, S. P, Ward, J. E, Weekes, T. C, Weinstein, A, Weisgarber, T, Williams, D. A, Wood, M, Aleksić, J, González, J. Becerra, Bednarek, W, Berger, K, Biland, A, Bonnoli, G, Bordas, P, Braun, I, Contreras, J. L, Dazzi, F, De Angelis, A, De Lotto, B, De Maria, M, De Sabata, F, Ferenc, D, Fonseca, M. V, López, R. J. García, Gaug, M, Giavitto, G, Godinović, N, Hadasch, D, Herrero, A, Höhne-Mönch, D, Klepser, S, La Barbera, A, Lindfors, E, Lombardi, S, Longo, F, López, M, Mannheim, K, Maraschi, L, Mariotti, M, Martínez, M, Meucci, M, Miranda, J. M, Moldón, J, Moralejo, A, Nieto, D, Orito, R, Paoletti, R, Pauss, F, Pegna, R. G, Perez-Torres, M. A, Reichardt, I, Reinthal, R, Rhode, W, Rico, J, Saggion, A, Salvati, M, Scalzotto, V, Schweizer, T, Sobczynska, D, Stamerra, A, Steinke, B, Storz, J, Strah, N, Takalo, L, Tavecchio, F, Terzić, T, Vankov, H, Weitzel, Q, Zandanel, F, Zanin, R
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.03.2011; IOP; Institute of Physics (IOP)
• Subjects: Active galaxies; Astronomy; ASTRONOMY AND ASTROPHYSICS; BL Lacertae objects: individual (Markarian 501 = Earth, ocean, space; Exact sciences and technology; galaxies: active; Galàxies actives; Gamma rays; gamma rays: galaxies; radiation mechanisms: non-thermal; Raigs gamma; Raigs X; VER J1653+397; X-rays; X-rays: galaxies; radiation mechanisms: non-thermal; X-ray galaxies; Variability; X-rays: galaxies; Spectral energy distribution; Cosmic x-ray sources; Luminosity; BL Lacertae objects: individual (Markarian 501 = VER J1653+397); Blazar; BL Lacertae objects; Active galaxies; Radiation mechanism; Gamma radiation; galaxies: active; Active galaxy nuclei; Galaxy nuclei; Cosmic radio sources; Jets; Multifrequency observation; Models; gamma rays: galaxies; Very high energy
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/729/1/2

The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Mrk 501 was coordinated in 2009 March, focusing around a multi-day observation with the Suzaku X-ray satellite and including Delta *g-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Mrk 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of 1997 April 16, with the goal of examining variability of the spectral energy distribution (SED) between the two states. The derived broadband SED shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina (KN) regime. Synchrotron self-Compton models are matched to the data and the implied KN effects are explored.