Fermi-large area telescope observations of the exceptional gamma-ray outbursts of 3C 273 in 2009 September

Abdo, Aa; Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, Rd; Bloom, Ed; Bonamente, E; Borgland, Aw; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, Th; Buson, S; Caliandro, Ga; Cameron, Ra; Cannon, A; Caraveo, Pa; Carrigan, S; Casandjian, Jm; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Costamante, L; Dermer, Cd; de Angelis, A; de Palma, F; Ede, Silva; Drell, Ps; Dubois, R; Dumora, D; Farnier, C; Favuzzi, Cecilia; Fegan, Sj; Focke, Wb; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, Nicola; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, Ia; Grondin, Mh; Guiriec, S; Hayashida, M; Hays, E; Hill, Ab; Horan, D; Hughes, Re; Johannesson, G; Johnson, As; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine Goumard, M; Garde, Ml; Longo, F; Loparco, F; Lott, B; Lovellette, Mn; Lubrano, P; Madejski, Gm; Makeev, A; Mansutti, O; Massaro, E; Mazziotta, Mn; Mcconville, W; Mcenery, Je; Meurer, C; Michelson, Pf; Mitthumsiri, W; Mizuno, T; Moiseev, Aa; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, Jf; Paneque, D; Panetta, Jh; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Porter, Ta; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Rodriguez, Ay; Romani, Rw; Roth, M; Ryde, F; Hfw, Sadrozinski; Sander, A; Scargle, Jd; Schalk, Tl; Sgro, C; Siskind, Ej; Smith, Pd; Spandre, G; Spinelli, P; Starck, Jl; Strickman, Ms; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vasileiou, V; Vilchez, N; Vitale, V; Waite, Ap; Wang, P; Wehrle, Ae; Winer, Bl; Wood, Ks; Yang, Z; Ylinen, T; Ziegler, M.

doi:10.1088/2041-8205/714/1/L73

We present the light curves and spectral data of two exceptionally luminous gamma-ray outbursts observed by the Large Area Telescope experiment on board the Fermi Gamma-ray Space Telescope from 3C 273 in 2009 September. During these flares, having a duration of a few days, the source reached its highest gamma-ray flux ever measured. This allowed us to study, in some details, their spectral and temporal structures. The rise and the decay are asymmetric on timescales of 6 hr, and the spectral index was significantly harder during the flares than during the preceding 11 months. We also found that short, very intense flares put out the same time-integrated energy as long, less intense flares like that observed in 2009 August.

Fermi-large area telescope observations of the exceptional gamma-ray outbursts of 3C 273 in 2009 September / Abdo, Aa; Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, Rd; Bloom, Ed; Bonamente, E; Borgland, Aw; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, Th; Buson, S; Caliandro, Ga; Cameron, Ra; Cannon, A; Caraveo, Pa; Carrigan, S; Casandjian, Jm; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Costamante, L; Dermer, Cd; de Angelis, A; de Palma, F; Silva, Ede; Drell, Ps; Dubois, R; Dumora, D; Farnier, C; Favuzzi, Cecilia; Fegan, Sj; Focke, Wb; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, Nicola; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, Ia; Grondin, Mh; Guiriec, S; Hayashida, M; Hays, E; Hill, Ab; Horan, D; Hughes, Re; Johannesson, G; Johnson, As; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine Goumard, M; Garde, Ml; Longo, F; Loparco, F; Lott, B; Lovellette, Mn; Lubrano, P; Madejski, Gm; Makeev, A; Mansutti, O; Massaro, E; Mazziotta, Mn; Mcconville, W; Mcenery, Je; Meurer, C; Michelson, Pf; Mitthumsiri, W; Mizuno, T; Moiseev, Aa; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, Jf; Paneque, D; Panetta, Jh; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Porter, Ta; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Rodriguez, Ay; Romani, Rw; Roth, M; Ryde, F; Sadrozinski, Hfw; Sander, A; Scargle, Jd; Schalk, Tl; Sgro, C; Siskind, Ej; Smith, Pd; Spandre, G; Spinelli, P; Starck, Jl; Strickman, Ms; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vasileiou, V; Vilchez, N; Vitale, V; Waite, Ap; Wang, P; Wehrle, Ae; Winer, Bl; Wood, Ks; Yang, Z; Ylinen, T; Ziegler, M.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 714:1(2010), pp. L73-L78. [10.1088/2041-8205/714/1/L73]