Properties of Short GRB Pulses in the Fourth BATSE Catalog: Implications for the Structure and Evolution of the Jetted Outflows

Abstract

Considering the shortage of comparative studies on pulse temporal characteristics between singlepeaked short gamma-ray bursts (sGRBs) and double-peaked sGRBs, we examine the pulse properties of a sample of 100 BATSE sGRBs using the BATSE Time-Tagged Event (TTE) data with a 5-ms resolution. 243 individual pulses of the single-peaked, double-peaked and triple-peaked sGRBs are fitted to get their statistical properties such as the pulse asymmetry, amplitude, peak time, and pulse width, etc. For the double-peaked sGRBs, according to the overlapping ratio between two adjacent peaks, we first define two kinds of double-peaked sGRBs as M-loose and M-tight types and find that most of the first pulses are similar to the single-peaked ones. We study the dependence of the Full Width at Half Maximum (FWHM) on the photon energy among different energy bands. Interestingly, it is found that a power-law relation with an index of -0.4 does exist between the FWHM and the photon energy for the single-and double-peaked sGRBs. More interestingly, we notice that the powerlaw relation with a positive index also exist for several special short bursts. In view of the three typical timescales of pulses, namely the angular spreading timescale, the dynamic timescale, and the cooling timescale, we propose that the diverse power-law indexes together with the profile evolution of GRB pulse can be used as an effective probe to diagnose the structure and evolution of the relativistically jetted outflows.

Temporal Properties of Precursors, Main peaks and Extended Emissions of Short GRBs in the Third Swift/BAT GRB Catalog

“…Additionally, Figure 15 (a1)(a2) illustrate that the f m values of the main peaks are generally larger than those of the other two components. On the other hand, the photon fluxes of main peaks and the other two components seem to be positively correlated, indicating that the luminosities of the main peaks are linked to those of the precursors and the EE components, agreement with the results of Zhang et al (2020) and von Kienlin et al (2019). Moreover, it in return hints that the three parts of prompt gamma ray emissions could be produced from the same progenitor.…”

“…Lien et al (2016) reported the fraction of sGRBs with EE to be 1.19% in the third Swift/BAT catalog. Here, we extend our search to include the GRBs with EE tails reported in literatures (e.g., Norris & Bonnell 2006;Kisaka et al 2017;Yu et al 2020;Zhang et al 2020). According to von Kienlin et al (2019), we adopt the following three criteria:…”

Temporal Analysis of GRB Precursors in the Third Swift-BAT Catalog

“…It was found that the precursors are only slightly softer than the main bursts. Li et al (2020) obtained a short GRB precursor sample in the BATSE catalog. The angular spreading timescale and the cooling timescale were considered in the jet-cocoon scenario.…”

Overall spectral properties of prompt emissions with diverse segments inSwift/BAT short gamma-ray bursts

“…Recently, we defined two kinds of double-peaked BATSE sGRBs as M-loose and M-tight types according to the overlapping ratios between two adjacent main peaks (see Fig. 1 in Li et al 2020a). Then we examined the temporal properties of the main peaks and the other two components of Swift/BAT sGRBs (Li et al 2021).…”