Vestrand WT, Wozniak PR, Wren JA, Fenimore EE, Sakamoto T, White RR, Casperson D, Davis H, Evans S, Galassi M, McGowan KE, Schier JA, Asa JW, Barthelmy SD, Cummings JR, Gehrels N, Hullinger D, Krimm HA, Markwardt CB, McLean K, Palmer D, Parsons A, Tueller J. A link between prompt optical and prompt γ-ray emission in γ-ray bursts.
Nature 2005;
435:178-80. [PMID:
15889084 DOI:
10.1038/nature03515]
[Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 03/01/2005] [Indexed: 11/08/2022]
Abstract
The prompt optical emission that arrives with the gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions with the surroundings. Until now, only GRB 990123 had been detected at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma-ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta's collision with surrounding material. Here we report prompt optical emission from GRB 041219a. It is variable and correlated with the prompt gamma-rays, indicating a common origin for the optical light and the gamma-rays. Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine. The correlated optical emission is a direct probe of the jet isolated from the medium. The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium.
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