Chattopadhyay 2007 伽玛暴可分三类

主要内容:
把原来的长暴再分为低亮度（各向同性能10^52erg）和高亮度的。认为短暴、低亮长暴和高亮长暴分别来源于：双中子星、中子星白矮星并合和大质量恒星坍缩。

精彩摘抄:


文章信息:
arXiv:0705.4020 [ps, pdf, other] : Title: Statistical Evidence for Three classes of Gamma-ray Bursts
Authors: {Tanuka Chattopadhyay (Dinobundhoo Coll.), Ranjeev Misra (IUCAA), Asis Kumar Chattopadhyay (Dept. of Statistics, Calcutta Univ.), Malay Naskar (NIRJAIT)
Comments: 7 pages, accepted for publication in the Astrophysical Journal

Two different multivariate clustering techniques, the K-means partitioning method and the Dirichlet process of mixture modeling, have been applied to the BATSE Gamma-ray burst (GRB) catalog, to obtain the optimum number of coherent groups. In the standard paradigm, GRB are classified in only two groups, the long and short bursts. However, for both the clustering techniques, the optimal number of classes was found to be three, a result which is consistent with previous statistical analysis. In this classification, the long bursts are further divided into two groups which are primarily differentiated by their total fluence and duration and hence are named low and high fluence GRB. Analysis of GRB with known red-shifts and spectral parameters suggests that low fluence GRB have nearly constant isotropic energy output of 10^{52} ergs while for the high fluence ones, the energy output ranges from 10^{52} to 10^{54} ergs. It is speculated that the three kinds of GRB reflect three different origins which may be mergers of neutron star systems, white dwarf with neutron stars and collapse of massive stars.