Статья

GRB 061121: Broadband Spectral Evolution through the Prompt and Afterglow Phases of a Bright Burst

K. L. PageDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKR. WillingaleDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKJ. P. OsborneDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKB. ZhangDepartment of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154-4002O. GodetDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKF. E. MarshallNASA Goddard Space Flight Center, Greenbelt, MD 20771A. MelandriAstrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD, UKJ. P. NorrisDenver Research Institute, University of Denver, Denver, CO 80208P. T. O’BrienDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKV. Pal’shinIoffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, Saint Petersburg 194021, Russian FederationE. RolDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKP. RomanoDipartimento di Fisica, Universitá di Milano-Bicocca, I-20126 Milano, ItalyR. L. C. StarlingDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKP. SchadyMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UKS. A. YostUniversity of Michigan, Ann Arbor, MI 48104S. D. BarthelmyNASA Goddard Space Flight Center, Greenbelt, MD 20771A. P. BeardmoreDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKG. CusumanoINAF-IASF, Sezione di Palermo, 90146 Palermo, ItalyD. N. BurrowsDepartment of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802M. De PasqualeMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UKM. EhleXMM-Newton Science Operations Centre, European Space Agency, Villafranca del Castillo, E-28080 Madrid, SpainP. A. EvansDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKN. GehrelsNASA Goddard Space Flight Center, Greenbelt, MD 20771M. R. GoadDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKS. GolenetskiiIoffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, Saint Petersburg 194021, Russian FederationC. GuidorziDipartimento di Fisica, Universitá di Milano-Bicocca, I-20126 Milano, ItalyC. MundellAstrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD, UKM. J. PageMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UKG. RickerCenter for Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139T. SakamotoNASA Goddard Space Flight Center, Greenbelt, MD 20771B. E. SchaeferDepartment of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803M. StamatikosNASA Goddard Space Flight Center, Greenbelt, MD 20771E. TrojaDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKM. UlanovIoffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, Saint Petersburg 194021, Russian FederationF. YuanUniversity of Michigan, Ann Arbor, MI 48104H. ZiaeepourDipartimento di Fisica, Universitá di Milano-Bicocca, I-20126 Milano, Italy

2007en

ABI

Аннотация

Swift triggered on a precursor to the main burst of GRB 061121 (z=1.314), allowing observations to be made from the optical to gamma-ray bands. Many other telescopes, including Konus-Wind, XMM-Newton, ROTSE, and the Faulkes Telescope North, also observed the burst. The gamma-ray, X-ray, and UV/optical emission all showed a peak ~75 s after the trigger, although the optical and X-ray afterglow components also appear early on, before or during the main peak. Spectral evolution was seen throughout the burst, with the prompt emission showing a clear positive correlation between brightness and hardness. The SED of the prompt emission, stretching from 1 eV up to 1 MeV, is very flat, with a peak in the flux density at ~ 1 keV. The optical to X-ray spectra at this time are better fitted by a broken, rather than single, power law, similar to previous results for X-ray flares. The SED shows spectral hardening as the afterglow evolves with time. This behavior might be a symptom of self-Comptonization, although circumstellar densities similar to those found in the cores of molecular clouds would be required. The afterglow also decays too slowly to be accounted for by the standard models. Although the precursor and main emission show different spectral lags, both are consistent with the lag-luminosity correlation for long bursts. GRB 061121 is the instantaneously brightest long burst yet detected by Swift. Using a combination of Swift and Konus-Wind data, we estimate an isotropic energy of 2.8×1053 ergs over 1 keV-10 MeV in the GRB rest frame. A probable jet break is detected at ~2×105 s, leading to an estimate of ~10 51 ergs for the beaming-corrected gamma-ray energy.

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Идентификаторы

DOI: 10.1086/518821

Цитирования и источники

Цитирований: 3Использованных источников: 0

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