Abdo AA, Ackermann M, Ajello M, Asano K, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Bhat PN, Bissaldi E, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bouvier A, Bregeon J, Brez A, Briggs MS, Brigida M, Bruel P, Burgess JM, Burrows DN, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Connaughton V, Conrad J, Cutini S, D'Elia V, Dermer CD, De Angelis A, De Palma F, Digel SW, Dingus BL, Do Couto E Silva E, Drell PS, Dubois R, Dumora D, Farnier C, Favuzzi C, Fegan SJ, Finke J, Fishman G, Focke WB, Fortin P, Frailis M, Fukazawa Y, Funk S, Fusco P, Gargano F, Gehrels N, Germani S, Giavitto G, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Goldstein A, Granot J, Greiner J, Grenier IA, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Horan D, Hughes RE, Jackson MS, Johannesson G, Johnson AS, Johnson RP, Johnson WN, Kamae T, Katagiri H, Kataoka J, Kawai N, Kerr M, Kippen RM, Knoedlseder J, Kocevski D, Komin N, Kouveliotou C, Kuss MW, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Mazziotta MN, Mcbreen S, Mcenery JE, Mcglynn S, Meegan C, Meszaros P, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Moretti E, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nolan PL, Norris JP, Nuss E, Ohno M, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paciesas WS, Paneque D, Panetta JH, Pelassa V, Pepe M, Pesce-Rollins M, Petrosian V, Piron F, Porter TA, Preece R, Raino S, Rando R, Rau A, Razzano M, Razzaque S, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Roming PWA, Roth M, Ryde F, Sadrozinski HFW, Sanchez D, Sander A, Parkinson PMS, Scargle JD, Schalk TL, Sgro C, Siskind EJ, Smith PD, Spinelli P, Stamatikos M, Stecker FW, Stratta G, Strickman MS, Suson DJ, Swenson CA, Tajima H, Takahashi HH, Tanaka T, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Uehara T, Usher TL, Van Der Horst AJ, Vasileiou V, Vilchez N, Vitale V, Von Kienlin A, Waite AP, Wang P, Wilson-Hodge C, Winer BL, Wood KS, Yamazaki R, Ylinen T, Ziegler M (2009)
Publication Type: Journal article
Publication year: 2009
Book Volume: 706
Pages Range: L138-L144
Journal Issue: 1
DOI: 10.1088/0004-637X/706/1/L138
We report on the observation of the bright, long gamma-ray burst (GRB), GRB 090902B, by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments on-board the Fermi observatory. This was one of the brightest GRBs to have been observed by the LAT, which detected several hundred photons during the prompt phase. With a redshift of z = 1.822, this burst is among the most luminous detected by Fermi. Time-resolved spectral analysis reveals a significant power-law component in the LAT data that is distinct from the usual Band model emission that is seen in the sub-MeV energy range. This power-law component appears to extrapolate from the GeV range to the lowest energies and is more intense than the Band component, both below similar to 50 keV and above 100 MeV. The Band component undergoes substantial spectral evolution over the entire course of the burst, while the photon index of the power-law component remains constant for most of the prompt phase, then hardens significantly toward the end. After the prompt phase, power-law emission persists in the LAT data as late as 1 ks post-trigger, with its flux declining as t(-1.5). The LAT detected a photon with the highest energy so far measured from a GRB, 33.4(-3.5)(+ 2.7) GeV. This event arrived 82 s after the GBM trigger and similar to 50 s after the prompt phase emission had ended in the GBM band. We discuss the implications of these results for models of GRB emission and for constraints on models of the extragalactic background light.
APA:
Abdo, A.A., Ackermann, M., Ajello, M., Asano, K., Atwood, W.B., Axelsson, M.,... Ziegler, M. (2009). FERMI OBSERVATIONS OF GRB 090902B: A DISTINCT SPECTRAL COMPONENT IN THE PROMPT AND DELAYED EMISSION. Astrophysical Journal Letters, 706(1), L138-L144. https://dx.doi.org/10.1088/0004-637X/706/1/L138
MLA:
Abdo, A. A., et al. "FERMI OBSERVATIONS OF GRB 090902B: A DISTINCT SPECTRAL COMPONENT IN THE PROMPT AND DELAYED EMISSION." Astrophysical Journal Letters 706.1 (2009): L138-L144.
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