Search for Discrete X-ray Spectral Features in a Sample of Bright Gamma-ray Burst Afterglows.

Sako, M.

Technical Information Center Oak Ridge Tennessee

关键词: Afterglow;    Cosmic gamma bursts;    X-ray spectra;    Spectral response;    X radiation;   

RP-ID  :  DE2004833044

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We present uniform, detailed spectral analyses of gamma-ray burst (GRB) X-ray afterglows observed with ASCA, Beppo-SAX, Chandra, and XMM-Newton, and critically evaluate the statistical significances of X-ray emission and absorption features in these spectra. The sample consists of 21 X-ray afterglow observations up to and including that of GRB040106 with spectra of sufficient statistical quality to allow meaningful line searches, chosen here somewhat arbitrarily to be detections with more than 100 total (source plus background) counts. This sample includes all nine X-ray afterglows with published claims of line detections. Moderate resolution spectra are available for 16 of the 21 sources, and for the remaining five the Chandra transmission grating spectrometers obtained high-resolution data. All of the data are available from the public archive. We test a simple hypothesis in which the observed spectra are produced by a power-law continuum model modified by photoelectric absorption by neutral material both in our Galaxy and possibly also local to the burst.