Impulsive and Varying Injection in Gamma-Ray Burst Afterglows
Impulsive and Varying Injection in Gamma-Ray Burst Afterglows
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DOI：
10.1086/312689
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发表时间：
2000-03
期刊：
影响因子：
--
通讯作者：
R. Sari;P. Mészáros
中科院分区：
文献类型：
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作者：
R. Sari;P. Mészáros
伽马射线暴余辉的标准模型是基于相对论抛射物与周围介质相遇时产生的冲击波的同步辐射。我们重新分析了刷新的激波情景，在这种情景中，较慢的物质赶上了减速的喷射物，并为其重新提供了能量。这种能量可以是连续的，也可以是离散的。我们表明，这种情况有两个重要的影响。首先，还有一个额外的成分来自反激波，它进入了被激发的喷射物。这种情况会持续到重启本身，这可能会持续几天或更长时间。我们发现，在这段时间内，总的光谱峰值出现在反向激波的特征频率处。其次，如果注入是连续的，则动力学将不同于恒定能量演化的动力学，并将导致观测通量的较慢下降。对持续刷新情景的一个简单测试是，它预测几天后在远红外或毫米范围内会出现光谱最大值。
The standard model of gamma-ray burst afterglows is based on synchrotron radiation from a blast wave produced when the relativistic ejecta encounters the surrounding medium. We reanalyze the refreshed shock scenario, in which slower material catches up with the decelerating ejecta and reenergizes it. This energization can be done either continuously or in discrete episodes. We show that such a scenario has two important implications. First, there is an additional component coming from the reverse shock that goes into the energizing ejecta. This persists for as long as the reenergization itself, which could extend for up to days or longer. We find that during this time the overall spectral peak is found at the characteristic frequency of the reverse shock. Second, if the injection is continuous, the dynamics will be different from that in constant energy evolution and will cause a slower decline of the observed fluxes. A simple test of the continuously refreshed scenario is that it predicts a spectral maximum in the far-infrared or millimeter range after a few days.