The Fermi GBM GRBs' multivariate statistics

TL;DR

This study analyzes gamma-ray burst spectra from Fermi and Swift satellites using multivariate statistics, revealing relationships between spectral categories and physical data, and comparing spectral types across instruments.

Contribution

It introduces a multivariate statistical approach to classify GRB spectra and compares spectral types between Fermi and Swift observations, highlighting the consistency and differences.

Findings

Relationship between spectral categories and physical data established

Connection found between Fermi and Swift spectra, especially in fluence data

Observation overlap does not imply selection effects in spectral behavior

Abstract

Studying the GRBs' gamma-ray spectra may reveal some physical information of Gamma-ray Bursts. The Fermi satellite observed more than two thousand GRBs. The FERMIGBRST catalog contains GRB parameters (peak energy, spectral indices, intensity) estimated for both the total emission (fluence), and the emission during the interval of the peak flux. We found a relationship with linear discriminant analysis between the spectral categories and the model independent physical data. We compared the Swift and Fermi spectral types. We found a connection between the Fermi fluence spectra and the Swift spectra but the result of the peak flux spectra can be disputable. We found that those GRBs which were observed by both Swift and Fermi can similarly discriminate as the complete Fermi sample. We concluded that the common observation probably did not mean any trace of selection effects in the spectral behavior of GRBs.