GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for similar to 24.5 s (in the GBM) and had a peak flux of (5.7 +/- 0.2) x 10(-5) erg s(-1) cm(-2). The time-resolved emission spectrum is best modeled with a combination of a Band function and a blackbody spectrum. The peak energy of the Band component was initially 15 +/- 2 MeV, which is the highest value ever detected in a GRB. This measurement was made possible by combining GBM/BGO data with LAT Low Energy events to achieve continuous 10-100 MeV coverage. The peak energy later decreased as a power law in time with an index of -1.89 +/- 0.10. The temperature of the blackbody component also decreased, starting from similar to 80 keV, and the decay showed a significant break after similar to 2 s. The spectrum provides strong constraints on the standard synchrotron model, indicating that alternative mechanisms may give rise to the emission at these energies.

GRB110721A: An extreme peak energy and signatures of the photosphere / Axelsson, M; Baldini, L; Barbiellini, G; Baring, Mg; Bellazzini, R; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Cecchi, C; Chaves, Rcg; Chekhtman, A; Chiang, J; Claus, R; Conrad, J; Cutini, S; D'Ammando, F; de Palma, F; Dermer, Cd; Silva, Ede; Drell, Ps; Favuzzi, Cecilia; Fegan, Sj; Ferrara, Ec; Focke, Wb; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, Nicola; Giroletti, M; Godfrey, G; Guiriec, S; Hadasch, D; Hanabata, Y; Hayashida, M; Hou, X; Iyyani, S; Jackson, Ms; Kocevski, D; Kuss, M; Larsson, J; Larsson, S; Longo, F; Loparco, F; Lundman, C; Mazziotta, Mn; Mcenery, Je; Mizuno, T; Monzani, Me; Moretti, E; Morselli, A; Murgia, S; Nuss, E; Nymark, T; Ohno, M; Omodei, N; Pesce Rollins, M; Piron, F; Pivato, G; Racusin, Jl; Raino, S; Razzano, M; Razzaque, S; Reimer, A; Roth, M; Ryde, F; Sanchez, Da; Sgro, C; Siskind, Ej; Spandre, G; Spinelli, P; Stamatikos, M; Tibaldo, L; Tinivella, M; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, Ap; Winer, Bl; Wood, Ks; Burgess, Jm; Bhat, Pn; Bissaldi, Elisabetta; Briggs, Ms; Connaughton, V; Fishman, G; Fitzpatrick, G; Foley, S; Gruber, D; Kippen, Rm; Kouveliotou, C; Jenke, P; Mcbreen, S; Mcglynn, S; Meegan, C; Paciesas, Ws; Pelassa, V; Preece, R; Tierney, D; von Kienlin, A; Wilson Hodge, C; Xiong, S; Pe'Er, A.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 757:2(2012). [10.1088/2041-8205/757/2/L31]

GRB110721A: An extreme peak energy and signatures of the photosphere

FAVUZZI, Cecilia;GIGLIETTO, Nicola;BISSALDI, Elisabetta;
2012-01-01

Abstract

GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for similar to 24.5 s (in the GBM) and had a peak flux of (5.7 +/- 0.2) x 10(-5) erg s(-1) cm(-2). The time-resolved emission spectrum is best modeled with a combination of a Band function and a blackbody spectrum. The peak energy of the Band component was initially 15 +/- 2 MeV, which is the highest value ever detected in a GRB. This measurement was made possible by combining GBM/BGO data with LAT Low Energy events to achieve continuous 10-100 MeV coverage. The peak energy later decreased as a power law in time with an index of -1.89 +/- 0.10. The temperature of the blackbody component also decreased, starting from similar to 80 keV, and the decay showed a significant break after similar to 2 s. The spectrum provides strong constraints on the standard synchrotron model, indicating that alternative mechanisms may give rise to the emission at these energies.
2012
GRB110721A: An extreme peak energy and signatures of the photosphere / Axelsson, M; Baldini, L; Barbiellini, G; Baring, Mg; Bellazzini, R; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Cecchi, C; Chaves, Rcg; Chekhtman, A; Chiang, J; Claus, R; Conrad, J; Cutini, S; D'Ammando, F; de Palma, F; Dermer, Cd; Silva, Ede; Drell, Ps; Favuzzi, Cecilia; Fegan, Sj; Ferrara, Ec; Focke, Wb; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, Nicola; Giroletti, M; Godfrey, G; Guiriec, S; Hadasch, D; Hanabata, Y; Hayashida, M; Hou, X; Iyyani, S; Jackson, Ms; Kocevski, D; Kuss, M; Larsson, J; Larsson, S; Longo, F; Loparco, F; Lundman, C; Mazziotta, Mn; Mcenery, Je; Mizuno, T; Monzani, Me; Moretti, E; Morselli, A; Murgia, S; Nuss, E; Nymark, T; Ohno, M; Omodei, N; Pesce Rollins, M; Piron, F; Pivato, G; Racusin, Jl; Raino, S; Razzano, M; Razzaque, S; Reimer, A; Roth, M; Ryde, F; Sanchez, Da; Sgro, C; Siskind, Ej; Spandre, G; Spinelli, P; Stamatikos, M; Tibaldo, L; Tinivella, M; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, Ap; Winer, Bl; Wood, Ks; Burgess, Jm; Bhat, Pn; Bissaldi, Elisabetta; Briggs, Ms; Connaughton, V; Fishman, G; Fitzpatrick, G; Foley, S; Gruber, D; Kippen, Rm; Kouveliotou, C; Jenke, P; Mcbreen, S; Mcglynn, S; Meegan, C; Paciesas, Ws; Pelassa, V; Preece, R; Tierney, D; von Kienlin, A; Wilson Hodge, C; Xiong, S; Pe'Er, A.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - 757:2(2012). [10.1088/2041-8205/757/2/L31]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/52012
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