GRB X-Ray Flare Properties among Different GRB Subclasses

• Published in: The Astrophysical journal Vol. 884; no. 1; pp. 59 - 78
• Main Authors: Liu, Chuanxi, Mao, Jirong
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.10.2019; IOP Publishing
• Subjects: Astrophysics; Emission; Emissions; Flares; Fluence; Gamma ray bursts; Gamma rays; gamma rays: general; Properties (attributes); radiation mechanisms: non-thermal; X ray flashes
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab3e75

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.