GRB X-Ray Flare Properties among Different GRB Subclasses

TL;DR

This study compares X-ray flare properties across different GRB subclasses, revealing significant differences in flare brightness, fluence ratios, and correlations, which may aid in classifying GRBs and understanding their nature.

Contribution

It provides a comprehensive analysis of X-ray flare characteristics among GRB subclasses, highlighting distinctions that improve classification and understanding of GRB diversity.

Findings

XRFs and XRRs have more bright X-ray flares than C-GRBs.

The fluence ratio distribution differs between XRF and C-GRB subclasses.

The correlation between flare duration and peak time varies among subclasses.

Abstract

Gamma-ray bursts (GRBs) can be divided into three subclasses: X-ray flash (XRF), X-ray rich (XRR), and classical GRB (C-GRB). An X-ray flare is the rebrightening emission shown in the early X-ray afterglow of some GRBs. In this paper, we comprehensively examine the X-ray flare properties among XRF, XRR, and C-GRB subclasses. We utilize the XRF, XRR, and C-GRB subclass samples obtained from the Swift-BAT3 catalog, and the X-ray flare observational properties are collected from Falcone et al., Chincarini et al., and Yi et al. We find that XRFs and XRRs have more bright X-ray flares than C-GRBs. The ratio of the X-ray flare fluence to the prompt emission fluence has different distributions between XRF and C-GRB subclasses. The linear correlation between the duration and the peak time of the X-ray flares is also different between XRF and C-GRB subclasses. We are inclined to identify the GRBs with the bright X-ray flares as XRFs or XRRs. We discuss some issues that are related to the XRF/XRR/C-GRB classification. We also caution the selection effects and the instrument bias in our investigation. Large samples are required in the future to further confirm our results.