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Spectral Evolution of Two High-Energy Gamma-Ray Bursts

Y. Kaneko·R. D. Preece·M. M. Gonzalez·B. L. Dingus·M. S. Briggs
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Abstract

The prompt emission of the gamma-ray bursts is found to be very energetic, releasing ~10^51 ergs in a flash. However, their emission mechanism remains unclear and understanding their spectra is a key to determining the emission mechanism. Many GRB spectra have been analyzed in the sub-MeV energy band, and are usually well described with a smoothly broken power-law model. We present a spectral analysis of two bright bursts (GRB910503 and GRB930506), using BATSE and EGRET spectra that cover more than four decades of energy (30 keV - 200 MeV). Our results show time evolutions of spectral parameters (low-energy & high-energy photon indices and break energy) that are difficult to reconcile with a simple shock-acceleration model.

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Y. Kaneko, R. D. Preece, M. M. Gonzalez, B. L. Dingus, M. S. Briggs. 2004-01-15. Spectral Evolution of Two High-Energy Gamma-Ray Bursts. https://doi.org/10.1029/156gm29

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