Year: 2010
Type: article
Abstract: The optical-infrared afterglow of the Large Area Telescope (LAT)-detected long-duration burst, GRB 090902B, has been observed by several instruments. The earliest detection by ROTSE-IIIa occurred 80 minutes after detection by the Gamma-ray Burst Monitor instrument on board the Fermi Gamma-Ray Space Telescope, revealing a bright afterglow and a decay slope suggestive of a reverse shock origin. Subsequent optical-IR observations followed the light curve for 6.5 days. The temporal and spectral behavior at optical-infrared frequencies is consistent with synchrotron fireball model predictions; the cooling break lies between optical and XRT frequencies ∼1.9 days after the burst. The inferred electron energy index is p = 1.8 ± 0.2, which would however imply an X-ray decay slope flatter than observed. The XRT and LAT data have similar spectral indices and the observed steeper value of the LAT temporal index is marginally consistent with the predicted temporal decay in the radiative regime of the forward shock model. Absence of a jet break during the first 6 days implies a collimation-corrected γ-ray energy E γ > 2.2 × 10 52 erg, one of the highest ever seen in a long-duration gamma-ray bursts. More events combining GeV photon emission with multiwavelength observations will be required to constrain the nature of the central engine powering these energetic explosions and to explore the correlations between energetic quanta and afterglow emission.
Source: The Astrophysical Journal
Authors: S. B. Pandey, C. A. Swenson, D. A. Perley, C. Guidorzi, K. Wiersema, D. Malesani, C. Akerlof, M. C. B. Ashley, D. Bersier, Z. Cano, A. Gomboc, I. Ilyin, P. Jakobsson, I. K. W. Kleiser, S. Kobayashi, C. Kouveliotou, A. J. Levan, T. A. McKay, A. Melandri, C. J. Mottram, C. G. Mundell, P. T. O’Brien, A. Phillips, J. M. Rex, M. H. Siegel, R. J. Smith, I. A. Steele, G. Stratta, N. R. Tanvir, D. Weights, S. A. Yost, F. Yuan, W. Zheng
Institutions: University of Michigan, Pennsylvania State University, University of California, Berkeley, University of Ferrara, University of Leicester, University of Copenhagen, UNSW Sydney, University of Ljubljana, Leibniz Institute for Astrophysics Potsdam, University of Iceland, Marshall Space Flight Center, National Space Science and Technology Center, University of Warwick, University of Hertfordshire, College of Saint Benedict and Saint John's University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2163987341