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arXiv 0908.2807astro-ph.HE
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单个费米伽玛暴的光谱-亮度关系

Spectral-Luminosity relation within individual Fermi GRBs

G. Ghirlanda, L. Nava, G. Ghisellini

摘要:

本文研究了费米卫星探测到的所有已知红移的长伽马射线暴的光谱。它们的通量和注量是足够大的,以允许在8千电子伏-1兆电子伏的能量范围内的光谱特性的时间依赖性的研究。我们发现它们的EL(E)谱的峰值能量Ep与亮度在单个爆发中有显著的紧密相关。这种时间分辨的Ep-Liso相关性对于所有考虑的爆发都非常相似,并且具有类似于由几个不同卫星检测到的不同爆发的时间积分光谱定义的类似Ep-Liso相关性的斜率和归一化。对于一些考虑的伽玛暴,我们还可以研究在每个爆发内的单个脉冲的上升和衰减阶段期间的Ep-Liso相关性的行为,没有发现差异。我们的研究结果表明,存在一个类似的物理机制,操作不同的伽玛暴的持续时间,紧密联系的爆发亮度与峰值能量的光谱在不同的时间发出。这种物理机制在构成伽玛射线暴的单个脉冲的上升和衰减阶段是相同的。这些结果,同时要求一个强大的物理解释,强烈表明,Ep-Liso的光谱能量相关性,考虑到不同的爆发的时间积分光谱是真实的,而不是仪器选择效应的结果。

英文摘要:

We study the spectra of all long Gamma Ray Bursts (GRBs) of known redshift detected by the Fermi satellite. Their fluxes and fluences are large enough to allow a time dependent study of their spectral characteristics in the 8 keV-1 MeV energy range. We find that the peak energy Ep of their EL(E) spectrum correlates with the luminosity in a remarkable tight way within individual bursts. This time resolved Ep-Liso correlation is very similar for all the considered bursts, and has a slope and normalisation similar to the analogous Ep-Liso correlation defined by the time integrated spectra of different bursts detected by several different satellites. For a few of the considered GRBs, we could also study the behaviour of the Ep-Liso correlation during the rising and decaying phases of individual pulses within each burst, finding no differences. Our results indicate the presence of a similar physical mechanism, operating for the duration of different GRBs, linking tightly the burst luminosity with the peak energy of the spectrum emitted at different times. Such a physical mechanism is the same during the rise and decay phase of individual pulses composing a GRB. These results, while calling for a robust physical interpretation, strongly indicate that the Ep-Liso spectral energy correlation found considering the time integrated spectra of different bursts is real, and not the result of instrumental selection effects.

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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