Factor analysis of the long gamma-ray bursts

TL;DR

This study applies factor analysis to 197 long gamma-ray bursts to identify underlying variables influencing their spectral and temporal properties, revealing five key factors and challenging some existing redshift and spectral relations.

Contribution

It introduces a factor analysis approach to gamma-ray burst data, identifying five latent factors and questioning previous spectral-redshift correlations.

Findings

Five factors adequately describe burst properties

The $ ext{RE}_{ ext{pk}}$ spectral variable is significant

Pseudo-redshifts and Amati-relation are disfavored

Abstract

We study statistically 197 long gamma-ray bursts, detected and measured in detail by the BATSE instrument of the Compton Gamma-Ray Observatory. In the sample 10 variables, describing for any burst the time behavior of the spectra and other quantities, are collected. The factor analysis method is used to find the latent random variables describing the temporal and spectral properties of GRBs. The application of this particular method to this sample indicates that five factors and the $\REpk$ spectral variable (the ratio of peak energies in the spectrum) describe the sample satisfactorily. Both the pseudo-redshifts inferred from the variability, and the Amati-relation in its original form, are disfavored.