Classi cation of Gamma-Ray Burst durations using robust model-comparison techniques

Kulkarni, S and Desai, Shantanu (2016) Classi cation of Gamma-Ray Burst durations using robust model-comparison techniques. arXiv. pp. 1-11.

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Gamma-Ray Bursts (GRBs) have been conventionally bifurcated into two distinct categories dubbed "short" and "long", depending on whether their durations are less than or greater than two seconds respectively. However, many authors have pointed to the existence of a third class of GRBs with mean durations intermediate between the short and long GRBs. Here, we apply multiple model comparison techniques to verify these claims. For each category, we obtain the best-fit parameters by maximizing a likelihood function based on a weighted superposition of lognormal distributions. We then do model-comparison between each of these hypotheses by comparing the chi-square probabilities, Akaike Information criterion (AIC), and Bayesian Information criterion (BIC). We uniformly apply these techniques to GRBs from Swift (both observer and intrinsic frame), BATSE, BeppoSAX, and Fermi-GBM. We find that the Swift GRB distributions (in the observer frame) show evidence for three categories at about 2.4σ from difference in chi-squares and show decisive evidence in favor of the two components using both AIC and BIC. For all the other datasets, evidence for three components is either very marginal or not favored.

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IITH Creators:
IITH CreatorsORCiD
Desai, Shantanu
Item Type: Article
Uncontrolled Keywords: GRBs; Maximum Likelihood; Chi-Square; Bayesian Information Criterion; Model Comparison; Akaike Information Criterion
Subjects: Physics > Astronomy Astrophysics
Divisions: Department of Physics
Depositing User: Team Library
Date Deposited: 02 Jan 2017 04:34
Last Modified: 05 Sep 2017 06:19
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