Abstract
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 ∼ 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 +2.7 -3.5 GeV. This event arrived 82 s after the GBM trigger and ∼ 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.
| Original language | English |
|---|---|
| Pages (from-to) | L138-L144 |
| Journal | Astrophysical Journal |
| Volume | 706 |
| Issue number | 1 PART 2 |
| DOIs | |
| Publication status | Published - 2009 |
Keywords
- Gamma rays: bursts
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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Fermi observations of GRB 090902b : A distinct spectral component in the prompt and delayed emission. / Abdo, A. A.; Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bhat, P. N.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, P.; Burgess, J. M.; Burrows, D. N.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Connaughton, V.; Conrad, J.; Cutini, S.; D'Elia, V.; Dermer, C. D.; De Angelis, A.; De Palma, F.; Digel, S. W.; Dingus, B. L.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Finke, J.; Fishman, G.; Focke, W. B.; 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, I. A.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Johnson, R. P.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Komin, N.; Kouveliotou, C.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Mazziotta, M. N.; McBreen, S.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mészros, P.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paciesas, W. S.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Porter, T. A.; Preece, R.; Rainò, S.; Rando, R.; Rau, A.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Roming, P. W.A.; Roth, M.; Ryde, F.; Sadrozinski, H. F.W.; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spinelli, P.; Stamatikos, M.; Stecker, F. W.; Stratta, G.; Strickman, M. S.; Suson, D. J.; Swenson, C. A.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Uehara, T.; Usher, T. L.; Van Der Horst, A. J.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Von Kienlin, A.; Waite, A. P.; Wang, P.; Wilson-Hodge, C.; Winer, B. L.; Wood, K. S.; Yamazaki, R.; Ylinen, T.; Ziegler, M.
In: Astrophysical Journal, Vol. 706, No. 1 PART 2, 2009, p. L138-L144.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Fermi observations of GRB 090902b
T2 - A distinct spectral component in the prompt and delayed emission
AU - Abdo, A. A.
AU - Ackermann, M.
AU - Ajello, M.
AU - Asano, K.
AU - Atwood, W. B.
AU - Axelsson, M.
AU - Baldini, L.
AU - Ballet, J.
AU - Barbiellini, G.
AU - Baring, M. G.
AU - Bastieri, D.
AU - Bechtol, K.
AU - Bellazzini, R.
AU - Berenji, B.
AU - Bhat, P. N.
AU - Bissaldi, E.
AU - Blandford, R. D.
AU - Bloom, E. D.
AU - Bonamente, E.
AU - Borgland, A. W.
AU - Bouvier, A.
AU - Bregeon, J.
AU - Brez, A.
AU - Briggs, M. S.
AU - Brigida, M.
AU - Bruel, P.
AU - Burgess, J. M.
AU - Burrows, D. N.
AU - Buson, S.
AU - Caliandro, G. A.
AU - Cameron, R. A.
AU - Caraveo, P. A.
AU - Casandjian, J. M.
AU - Cecchi, C.
AU - Çelik, Ö
AU - Chekhtman, A.
AU - Cheung, C. C.
AU - Chiang, J.
AU - Ciprini, S.
AU - Claus, R.
AU - Cohen-Tanugi, J.
AU - Cominsky, L. R.
AU - Connaughton, V.
AU - Conrad, J.
AU - Cutini, S.
AU - D'Elia, V.
AU - Dermer, C. D.
AU - De Angelis, A.
AU - De Palma, F.
AU - Digel, S. W.
AU - Dingus, B. L.
AU - Do Couto E Silva, E.
AU - Drell, P. S.
AU - Dubois, R.
AU - Dumora, D.
AU - Farnier, C.
AU - Favuzzi, C.
AU - Fegan, S. J.
AU - Finke, J.
AU - Fishman, G.
AU - Focke, W. B.
AU - Fortin, P.
AU - Frailis, M.
AU - Fukazawa, Y.
AU - Funk, S.
AU - Fusco, P.
AU - Gargano, F.
AU - Gehrels, N.
AU - Germani, S.
AU - Giavitto, G.
AU - Giebels, B.
AU - Giglietto, N.
AU - Giordano, F.
AU - Glanzman, T.
AU - Godfrey, G.
AU - Goldstein, A.
AU - Granot, J.
AU - Greiner, J.
AU - Grenier, I. A.
AU - Grove, J. E.
AU - Guillemot, L.
AU - Guiriec, S.
AU - Hanabata, Y.
AU - Harding, A. K.
AU - Hayashida, M.
AU - Hays, E.
AU - Horan, D.
AU - Hughes, R. E.
AU - Jackson, M. S.
AU - Jóhannesson, G.
AU - Johnson, A. S.
AU - Johnson, R. P.
AU - Johnson, W. N.
AU - Kamae, T.
AU - Katagiri, H.
AU - Kataoka, J.
AU - Kawai, N.
AU - Kerr, M.
AU - Kippen, R. M.
AU - Knödlseder, J.
AU - Kocevski, D.
AU - Komin, N.
AU - Kouveliotou, C.
AU - Kuss, M.
AU - Lande, J.
AU - Latronico, L.
AU - Lemoine-Goumard, M.
AU - Longo, F.
AU - Loparco, F.
AU - Lott, B.
AU - Lovellette, M. N.
AU - Lubrano, P.
AU - Madejski, G. M.
AU - Makeev, A.
AU - Mazziotta, M. N.
AU - McBreen, S.
AU - McEnery, J. E.
AU - McGlynn, S.
AU - Meegan, C.
AU - Mészros, P.
AU - Meurer, C.
AU - Michelson, P. F.
AU - Mitthumsiri, W.
AU - Mizuno, T.
AU - Moiseev, A. A.
AU - Monte, C.
AU - Monzani, M. E.
AU - Moretti, E.
AU - Morselli, A.
AU - Moskalenko, I. V.
AU - Murgia, S.
AU - Nakamori, T.
AU - Nolan, P. L.
AU - Norris, J. P.
AU - Nuss, E.
AU - Ohno, M.
AU - Ohsugi, T.
AU - Omodei, N.
AU - Orlando, E.
AU - Ormes, J. F.
AU - Paciesas, W. S.
AU - Paneque, D.
AU - Panetta, J. H.
AU - Pelassa, V.
AU - Pepe, M.
AU - Pesce-Rollins, M.
AU - Petrosian, V.
AU - Piron, F.
AU - Porter, T. A.
AU - Preece, R.
AU - Rainò, S.
AU - Rando, R.
AU - Rau, A.
AU - Razzano, M.
AU - Razzaque, S.
AU - Reimer, A.
AU - Reimer, O.
AU - Reposeur, T.
AU - Ritz, S.
AU - Rochester, L. S.
AU - Rodriguez, A. Y.
AU - Roming, P. W.A.
AU - Roth, M.
AU - Ryde, F.
AU - Sadrozinski, H. F.W.
AU - Sanchez, D.
AU - Sander, A.
AU - Saz Parkinson, P. M.
AU - Scargle, J. D.
AU - Schalk, T. L.
AU - Sgrò, C.
AU - Siskind, E. J.
AU - Smith, P. D.
AU - Spinelli, P.
AU - Stamatikos, M.
AU - Stecker, F. W.
AU - Stratta, G.
AU - Strickman, M. S.
AU - Suson, D. J.
AU - Swenson, C. A.
AU - Tajima, H.
AU - Takahashi, H.
AU - Tanaka, T.
AU - Thayer, J. B.
AU - Thayer, J. G.
AU - Thompson, D. J.
AU - Tibaldo, L.
AU - Torres, D. F.
AU - Tosti, G.
AU - Tramacere, A.
AU - Uchiyama, Y.
AU - Uehara, T.
AU - Usher, T. L.
AU - Van Der Horst, A. J.
AU - Vasileiou, V.
AU - Vilchez, N.
AU - Vitale, V.
AU - Von Kienlin, A.
AU - Waite, A. P.
AU - Wang, P.
AU - Wilson-Hodge, C.
AU - Winer, B. L.
AU - Wood, K. S.
AU - Yamazaki, R.
AU - Ylinen, T.
AU - Ziegler, M.
PY - 2009
Y1 - 2009
N2 - 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 ∼ 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 +2.7 -3.5 GeV. This event arrived 82 s after the GBM trigger and ∼ 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.
AB - 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 ∼ 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 +2.7 -3.5 GeV. This event arrived 82 s after the GBM trigger and ∼ 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.
KW - Gamma rays: bursts
UR - http://www.scopus.com/inward/record.url?scp=77649210676&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77649210676&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/706/1/L138
DO - 10.1088/0004-637X/706/1/L138
M3 - Article
AN - SCOPUS:77649210676
VL - 706
SP - L138-L144
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 PART 2
ER -