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J/ApJ/508/314       Gamma-ray bursts types                   (Mukherjee+, 1998)

Three types of gamma-ray bursts. Mukherjee S., Feigelson E.D., Babu J.G., Murtagh F., Fraley C., Raftery A. <Astrophys. J. 508, 314 (1998)> =1998ApJ...508..314M
ADC_Keywords: Gamma rays Keywords: gamma rays: bursts - methods: data analysis - methods: statistical Abstract: A multivariate analysis of gamma-ray burst (GRB) bulk properties is presented to discriminate between distinct classes of GRBs. Several variables representing burst duration, fluence, and spectral hardness are considered. Two multivariate clustering procedures are used on a sample of 797 bursts from the Third BATSE Catalog, a nonparametric average linkage hierarchical agglomerative clustering procedure validated with Wilks' {LAMBDA}* (1932, Biometrika, 24, 471) and other multivariate analysis of variance tests and a parametric maximum likelihood model-based clustering procedure assuming multinormal populations calculated with the Expectation-Maximization algorithm and validated with the Bayesian Information Criterion. The two methods yield very similar results. The BATSE GRB population consists of three classes with the following duration/fluence/spectrum bulk properties: class I with long/bright/soft bursts, class II with short/faint/hard bursts, and class III with intermediate/intermediate/soft bursts. One outlier due to spurious data is also present. Classes I and II correspond to those reported by Kouveliotou et al., but class III is clearly defined here for the first time. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 7 797 Burst classes from average linkage clustering (3B trigger number)
See also: IX/20 : The Fourth BATSE Burst Catalog (Paciesas+ 1998) Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1 A1 --- Class [ABCD] (1) 3- 6 I4 ---- Burst Burst number 7 A1 --- Note [*] Note (2)
Note (1): A: Class I (486 Bursts) long/bright/intermediate bursts B: Class II (203 Bursts), short/faint/hard,group C: Class III (107 Bursts) with intermediate/intermediate/soft properties D: Class IV (1 Burst) Note (2): In C class, all bursts are placed into class III by Gaussian model-based clustering procedure except burst marked * which is placed into class II
History: From ApJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 04-Feb-1999
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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