Classification of BeppoSAX's Gamma-Ray Bursts

TL;DR

This paper analyzes the duration distribution of 1003 GRBs from the BeppoSAX catalog, identifying an intermediate group and confirming the underrepresentation of short bursts due to detection system differences.

Contribution

It applies the Maximum Likelihood method to identify GRB groups in BeppoSAX data, notably confirming the intermediate group and discussing detection biases.

Findings

Identification of an intermediate GRB group in BeppoSAX data

Short bursts are underrepresented due to detection system differences

Multiple satellites observe the intermediate GRB type

Abstract

The BeppoSAX Catalog has been very recently published. In this paper we analyze - using the Maximum Likelihood (ML) method - the duration distribution of the 1003 GRBs listed in the catalog with duration. The ML method can identify the long and the intermediate duration groups. The short population of the bursts is identified only at a 96% significance level. MC simulation has been also applied and gives a similar significance level; 95%. However, the existence of the short bursts is not a scientific question after the Compton Gamma-Ray Observatory's observation. Our minor result is this well-known fact that in the BeppoSAX data the short bursts are underrepresented, mainly caused by the different triggering system. Our major result is the identification of the intermediate group in the BeppoSAX data. Therefore, four different satellites (CGRO, Swift, RHESSI and BeppoSAX) observed the intermediate type Gamma-Ray Burst.