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arXiv 0708.2763astro-ph
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用光谱截止能量诊断GRB瞬发发射场

Diagnosing GRB Prompt Emission Site with Spectral Cut-Off Energy

Nayantara Gupta, Bing Zhang

摘要:

伽马射线暴(GRB)瞬发的位置和机制至今仍不清楚。虽然内部冲击已被广泛讨论的伽玛暴的发射地点,支持其他发射地点的证据最近也提出了建议,包括近在光球的火球变得透明和更远的半径附近的火球减速半径磁耗散可能是重要的。随着GLAST实验的成功运行,在不久的将来,许多伽玛暴的瞬发高能辐射谱将被探测到。我们认为,从伽玛暴的即时发射光谱的截止能量取决于火球的体积洛伦兹因子和未知的发射半径从中央引擎。如果体洛伦兹因子可以独立测量(例如从早期余辉观测),观测到的光谱截止能量可以用来诊断伽马射线的发射部位。这将为理解伽玛暴promp辐射的物理起源提供有价值的信息。

英文摘要:

The site and mechanism of gamma-ray burst (GRB) prompt emission is still unknown. Although internal shocks have been widely discussed as the emission site of GRBs, evidence supporting other emission sites have been also suggested recently, including the closer-in photosphere where the fireball becomes transparent and further-out radii near the fireball deceleration radius where magnetic dissipation may be important. With the successful operation of the GLAST experiment, prompt high energy emission spectra from many GRBs would be detected in the near future. We suggest that the cut-off energy of the prompt emission spectrum from a GRB depends on both the fireball bulk Lorentz factor and the unknown emission radius from the central engine. If the bulk Lorentz factor could be independently measured (e.g. from early afterglow observations), the observed spectral cutoff energy can be used to diagnose the emission site of gamma-rays. This would provide valuable information to understand the physical origin of the GRB promp emission.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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