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Clues from the Prompt Emission of GRB 080319B

Zou, Yuan-Chuan and Piran, Tsvi and Sari, Re'em (2009) Clues from the Prompt Emission of GRB 080319B. Astrophysical Journal Letters, 692 (2). L92-L95. ISSN 2041-8205. doi:10.1088/0004-637X/692/2/L92.

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The extremely bright optical flash that accompanied GRB 080319B suggested, at first glance, that the prompt γ-rays in this burst were produced by synchrotron self-Compton (SSC). We analyze here the observed optical and γ spectra. We find that the very strong optical emission imposes, due to self-absorption, very strong constraints on the emission processes and puts the origin of the optical emission at a very large radius, almost inconsistent with internal shock. Alternatively, it requires a very large random Lorentz factor for the electrons. We find that SSC could not have produced the prompt γ-rays. We also show that the optical emission and the γ-rays could not have been produced by synchrotron emission from two populations of electrons within the same emitting region. Thus, we must conclude that the optical emission and the γ-rays were produced in different physical regions. A possible interpretation of the observations is that the γ-rays arose from internal shocks but the optical flash resulted from external shock emission. This would have been consistent with the few seconds delay observed between the optical and γ-ray signals.

Item Type:Article
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URLURL TypeDescription
Piran, Tsvi0000-0002-7964-5420
Sari, Re'em0000-0002-1084-3656
Additional Information:© 2009. The American Astronomical Society. Received 2008 December 5; accepted 2009 January 6; published 2009 January 28. Print publication: Issue 2 (2009 February 20). We thank P. Kumar, R. Mochkovitch, and Y. Fan for discussion. This work is supported by the Israel Science Foundation Center of Excellence in High Energy Astrophysics and by the Schwartzmann University Chair (T.P.), by a Marie Curie IRG and NASA ATP grant (R.S.), by the National Natural Science Foundation of China grant 10703002 and a Lady Davis Trust Post-Doctoral Fellowship (Y.C.Z.).
Funding AgencyGrant Number
Israel Science FoundationUNSPECIFIED
Hebrew University, JerusalemUNSPECIFIED
Marie Curie FellowshipUNSPECIFIED
National Natural Science Foundation (China)10703002
Lady Davis Fellowship TrustUNSPECIFIED
Subject Keywords:gamma rays: bursts; radiation mechanism: nonthermal
Issue or Number:2
Record Number:CaltechAUTHORS:ZOUapjl09
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13216
Deposited By: Archive Administrator
Deposited On:31 Jan 2009 01:37
Last Modified:08 Nov 2021 22:36

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