Generic Signatures of the Time Profiles of BATSE Cosmic Gamma-Ray Bursts
Generic Signatures of the Time Profiles of BATSE Cosmic Gamma-Ray Bursts
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BATSE 宇宙伽马射线暴时间剖面的通用特征
DOI：
10.1086/306093
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
C. Meegan
中科院分区：
文献类型：
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作者：
I. Mitrofanov;A. Pozanenko;M. Briggs;W. Paciesas;R. Preece;G. Pendleton;C. Meegan
提出了一种研究宇宙伽马射线暴时间历史的通用特征的新方法。我们对BATSE探测到的275个亮爆发的毫秒分辨时间分布进行了平均。通过主脉冲峰值处的最大计数数来归一化每个脉冲串的轮廓，并且通过相同的选择标准从归一化的轮廓中选择各个脉冲和脉间谷。引入了新的通用时间参数，它表征了每个脉冲的持续时间和等效宽度以及每个谷地的持续时间。总等效脉宽和总脉宽的直方图呈双峰分布。在单个脉冲的平均持续时间的直方图中也可以看到双峰现象。这些分布的短峰和长峰的爆发对应于第三个BATSE爆发目录T50和T90分布的两种模式。因此，这些新的爆发参数表明，观测到的双峰时间行为是伽马射线暴脉冲发射特性的结果。T90直方图长模式包括1~20个脉冲的爆发，对数平均脉冲宽度为1.17±0.09 S，多脉冲长事件的对数平均谷宽为1.28±0.15 S，短模式的爆发主要为单脉冲事件，对数平均脉冲宽度小得多，为0.2±0.01 S。研究了脉冲和谷沿脉冲串时间进程演变的基本特征。通过考虑这些特征，得出了关于伽马射线发射的物理结论。
A new method is proposed, which allows the study of generic signatures of cosmic gamma-ray burst time histories. We average the 64 ms resolution time profiles of 275 bright bursts detected by BATSE. The profile of each burst is normalized by the maximum number of counts at the peak of the primary pulse, and individual pulses and interpulse valleys are selected from the normalized profiles by identical selection criteria. New generic temporal parameters are introduced, which characterize the duration and equivalent width of each pulse and the duration of each valley. The histograms of the total equivalent pulse width and summed pulse duration are bimodal. Bimodality is also seen in the histogram of the mean duration of individual pulses. Bursts from the short and long peaks of these distributions correspond to the two modes of the Third BATSE Burst Catalog T50 and T90 distributions. Therefore, these new burst parameters demonstrate that the observed bimodal temporal behavior results from properties of the pulsed emission of gamma-ray bursts. The long mode of the T90 histogram includes bursts with from one to ~20 pulses; the logarithmic mean pulse duration is 1.17 ± 0.09 s; for the long events with more than one pulse, the logarithmic mean valley duration is 1.28 ± 0.15 s. Bursts of the short mode of T90 are mainly single-pulse events, and the logarithmic mean pulse duration is much smaller, 0.20 ± 0.01 s. For multipulse bursts of the T90 long mode, marginal correlations were found between the parameters of the pulses and valleys and the number of pulses. The basic signatures of the evolution of pulses and valleys along the time course of bursts are examined. Conclusions are drawn concerning the physics of gamma-ray emission by taking into account these signatures.