Fermi observations of GRB 090510: A short-hard gamma-ray burst with an additional, hard power-law component from 10 keV to GeV energies

M. Ackermann, K. Asano, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P. N. Bhat, E. Bissaldi, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. BregeonA. Brez, M. S. Briggs, M. Brigida, P. Bruel, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, C. Cecchi, Ö Çelik, E. Charles, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, C. D. Dermer, F. De Palma, B. L. Dingus, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, J. Finke, W. B. Focke, M. Frailis, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, J. Granot, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, A. K. Harding, E. Hays, D. Horan, R. E. Hughes, G. Jóhannesson, W. N. Johnson, T. Kamae, H. Katagiri, Jun Kataoka, N. Kawai, R. M. Kippen, J. Knödlseder, D. Kocevski, C. Kouveliotou, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, M. Llena Garde, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meegan, P. Mészros, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, H. Nakajima, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, W. S. Paciesas, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, R. Preece, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, S. Ritz, A. Y. Rodriguez, M. Roth, F. Ryde, H. F W Sadrozinski, A. Sander, J. D. Scargle, T. L. Schalk, C. Sgrò, E. J. Siskind, P. D. Smith, G. Spandre, P. Spinelli, M. Stamatikos, F. W. Stecker, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, K. Toma, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. Uehara, T. L. Usher, A. J. Van Der Horst, V. Vasileiou, N. Vilchez, V. Vitale, A. Von Kienlin, A. P. Waite, P. Wang, C. Wilson-Hodge, B. L. Winer, X. F. Wu, R. Yamazaki, Z. Yang, T. Ylinen, M. Ziegler

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    Abstract

    We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E peak = 3.9 ± 0.3MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 ± 0.03 that dominates the emission below ≈ 20keV and above ≈ 100MeV. The onset of the high-energy spectral component appears to be delayed by ≈ 0.1s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5+5.8 -2.6GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Γ≳1200, using simple γγ opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ≈ 100keV-few MeV flux. Stricter high confidence estimates imply Γ ≳ 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.

    Original languageEnglish
    Pages (from-to)1178-1190
    Number of pages13
    JournalAstrophysical Journal
    Volume716
    Issue number2
    DOIs
    Publication statusPublished - 2010

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    Keywords

    • Gamma-ray burst: individual (GRB 090510)
    • Radiation mechanisms: non-thermal

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Ackermann, 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., ... Ziegler, M. (2010). Fermi observations of GRB 090510: A short-hard gamma-ray burst with an additional, hard power-law component from 10 keV to GeV energies. Astrophysical Journal, 716(2), 1178-1190. https://doi.org/10.1088/0004-637X/716/2/1178