The flat spectrum radio quasar 3C 454.3 underwent an extraordinary outburst in 2009 December when it became the brightest gamma-ray source in the sky for over 1 week. Its daily flux measured with the Fermi-Large Area Telescope at photon energiesE > 100 MeV reached F(100) = 22 +/- 1 x 10(6) photon cm(-2) s(-1), representing the highest daily flux of any blazar ever recorded in high-energy. -rays. It again became the brightest source in the sky in 2010 April, triggering a pointed-mode observation by Fermi. The correlated. -ray temporal and spectral properties during these exceptional events are presented and discussed. The main results show flux variability over time scales less than 3 hr and very mild spectral variability with an indication of gradual hardening preceding major flares. The light curves during periods of enhanced activity in 2008 July-August and 2010 December show strong resemblance, with a flux plateau of a few days preceding the major flare. No consistent loop pattern emerged in the. -ray spectral index versus the flux plane as would be expected in acceleration and cooling scenarios. The maximum energy of a photon from 3C 454.3 is approximate to 20 GeV and a minimum Doppler factor of approximate to 13 is derived. The gamma-ray spectrum of 3C 454.3 shows a significant spectral break between approximate to 2 and 3 GeV that is very weakly dependent on the flux state, even when the flux changes by an order of magnitude.
Fermi gamma-ray space telescope observations of gamma-ray outbursts from 3C 454.3 in 2009 december and 2010 april / Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, Rd; Bonamente, E; Borgland, Aw; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Burnett, Th; Buson, S; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Carrigan, S; Casandjian, Jm; Cavazzuti, E; Cecchi, C; Celik, O; Chekhtman, A; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Corbel, S; Cutini, S; D'Ammando, F; Dermer, Cd; de Angelis, A; de Palma, F; Digel, Sw; Silva, Ede; Drell, Ps; Dubois, R; Dumora, D; Escande, L; Favuzzi, Cecilia; Fegan, Sj; Ferrara, Ec; Fuhrmann, L; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, Nicola; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, Ia; Grove, Je; Guiriec, S; Hadasch, D; Hayashida, M; Hays, E; Johannesson, G; Johnson, As; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lee, Sh; Garde, Ml; Longo, F; Loparco, F; Lott, B; Lubrano, P; Madejski, Gm; Makeev, A; Marchili, N; Mazziotta, Mn; Mcenery, Je; Mehault, J; Michelson, Pf; Mizuno, T; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Nakamori, T; Nalewajko, K; Naumann Godo, M; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Porter, Ta; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reyes, Lc; Ripken, J; Ritz, S; Roth, M; Sadrozinski, Hfw; Sanchez, D; Sander, A; Scargle, Jd; Sgro, C; Sikora, M; Siskind, Ej; Spandre, G; Spinelli, P; Strickman, Ms; Suson, Dj; Takahashi, H; Takahashi, T; Tanaka, T; Tanaka, Y; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Torres, Df; Tosti, G; Tramacere, A; Usher, Tl; Vandenbroucke, J; Vilchez, N; Vitale, V; Waite, Ap; Wang, P; Wehrle, Ae; Winer, Bl; Yang, Z; Ylinen, T; Ziegler, M.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - ELETTRONICO. - 721:2(2010), pp. 1383-1396. [10.1088/0004-637X/721/2/1383]
Fermi gamma-ray space telescope observations of gamma-ray outbursts from 3C 454.3 in 2009 december and 2010 april
FAVUZZI, Cecilia;GIGLIETTO, Nicola;
2010-01-01
Abstract
The flat spectrum radio quasar 3C 454.3 underwent an extraordinary outburst in 2009 December when it became the brightest gamma-ray source in the sky for over 1 week. Its daily flux measured with the Fermi-Large Area Telescope at photon energiesE > 100 MeV reached F(100) = 22 +/- 1 x 10(6) photon cm(-2) s(-1), representing the highest daily flux of any blazar ever recorded in high-energy. -rays. It again became the brightest source in the sky in 2010 April, triggering a pointed-mode observation by Fermi. The correlated. -ray temporal and spectral properties during these exceptional events are presented and discussed. The main results show flux variability over time scales less than 3 hr and very mild spectral variability with an indication of gradual hardening preceding major flares. The light curves during periods of enhanced activity in 2008 July-August and 2010 December show strong resemblance, with a flux plateau of a few days preceding the major flare. No consistent loop pattern emerged in the. -ray spectral index versus the flux plane as would be expected in acceleration and cooling scenarios. The maximum energy of a photon from 3C 454.3 is approximate to 20 GeV and a minimum Doppler factor of approximate to 13 is derived. The gamma-ray spectrum of 3C 454.3 shows a significant spectral break between approximate to 2 and 3 GeV that is very weakly dependent on the flux state, even when the flux changes by an order of magnitude.File | Dimensione | Formato | |
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