Ando, Shin'ichiro and Nakar, Ehud and Sari, Re'em (2008) GeV Emission from Prompt and Afterglow Phases of Gamma-Ray Bursts. Astrophysical Journal, 689 (2). pp. 1150-1160. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:ANDapj08
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We investigate the GeV emission from gamma-ray bursts (GRBs) using the results from the Energetic Gamma Ray Experimental Telescope (EGRET) and in view of the Gamma-Ray Large Area Space Telescope (GLAST). Assuming that the conventional prompt and afterglow photons originate from synchrotron radiation, we compare an accompanying inverse-Compton component with EGRET measurements and upper limits on GeV fluence, taking Klein-Nishina feedback into account. We find that the EGRET constraints are consistent with the theoretical framework of the synchrotron self-Compton model for both prompt and afterglow phases, and discuss constraints on microphysical parameters in both phases. Based on the inverse-Compton model and using EGRET results, we predict that GLAST would detect GRBs with GeV photons at a rate of ≳ 20 yr^-1 from both the prompt and afterglow phases. This rate applies to the high-energy tail of the prompt synchrotron emission and to the inverse-Compton component of the afterglow. Theory predicts that in a large fraction of the cases where synchrotron GeV prompt emission would be detected by GLAST, inverse-Compton photons should also be detected at high energies (≳ 10 GeV). Therefore, GLAST will enable a more precise test of the high-energy emission mechanism. Finally, we show that the contribution of GRBs to the flux of the extragalactic gamma-ray background measured with EGRET is at least 0.01%, and likely around 0.1%.
|Additional Information:||© 2008 The American Astronomical Society. Received 2007 August 6; accepted 2008 August 11. We are grateful to B. L. Dingus and M. M. Gonzalez Sanchez for very helpful comments and discussions. We thank the referee for useful comments. This work was supported by the Sherman Fairchild Foundation (S. A. and E. N.), a NASA Swift Grant (E. N.), the Alfred P. Sloan Foundation, the Packard Foundation, and a NASA ATP Grant (R. S.).|
|Subject Keywords:||gamma rays: bursts; radiation mechanisms: nonthermal|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||22 Apr 2009 22:03|
|Last Modified:||26 Dec 2012 10:48|
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