Related papers: Short vs Long and Collapsars vs. non-Collapsar: a …
Gamma-ray bursts (GRBs), the most energetic transients in the Universe, are traditionally classified into long-duration ($T_{90}>2$ s) and short-duration ($T_{90}<2$ s) events, associated with the core collapse of massive stars (Type II)…
We report the systematic analysis of the durations for Swift gamma-ray bursts (GRBs) and compare the results with those of pre-Swift data. For 95 GRBs with known redshift, we show that the observed durations have two lognormal distributions…
We review the T_90 duration and hardness ratio of Swift Gamma Ray Bursts (GRBs). We focus on GRBs with known redshift and review their gamma properties in the GRBs rest frames. We find that GRBs number vs. T_90/(1+z) distribution shows a…
Gamma-ray bursts (GRBs) have been phenomenologically classified into long and short populations based on the observed bimodal distribution of duration. Multi-wavelength and multi-messenger observations in recent years have revealed that in…
We report evidence from the 3B Catalogue that short (T_90 < 10 s) and long (T_90 > 10 s) GRB represent different populations and processes: Their spectral behavior is qualitatively different, with short bursts harder in the BATSE range, but…
We estimate the rate and the luminosity function of short (hard) Gamma-Ray Bursts (sGRBs) that are non-Collapsars, using the peak fluxes and redshifts of BATSE, Swift and Fermi GRBs. Following Bromberg2013 we select a sub-sample of Swift…
In the present paper, we investigated the distribution of hardness ratio (HR) for short and long gamma-ray bursts (GRBs) in different time scales for the first two seconds. After including and subtracting the background count, we performed…
Two classes of GRBs have been identified thus far without doubt and are prescribed to different physical scenarios -- NS-NS or NS-BH mergers, and collapse of massive stars, for short and long GRBs, respectively. The existence of two…
We present the results of a comprehensive study of the luminosity function, energetics, prompt gamma-ray correlations, and classification methodology of short-hard and long-soft GRBs (SGRBs and LGRBs), based on observational data in the…
Gamma Ray Burst (GRBs) are empirically classified as long-duration GRBs (LGRBs, $>$ 2s) and short-duration GRBs (SGRBs, $<$ 2s). Physically they can be grouped into two distinct progenitor categories: those originating from collapse of…
Gamma-ray bursts (GRBs) are typically classified into long and short GRBs based on their durations. However, there is a significant overlapping in the duration distributions of these two categories. In this paper, we apply the unsupervised…
In an effort to understand the puzzle of classifying gamma-ray bursts (GRBs), we perform a systematic study of {\it Swift} GRBs and investigate several short GRB issues. Though short GRBs have a short ($\lesssim2$ s) prompt duration as…
Gamma-ray bursts (GRBs) show a bimodal distribution of durations, separated at a duration of ~2 s. Observations have confirmed the association of long GRBs with the collapse of massive stars. The origin of short GRBs is still being…
We have carried out a detailed study of the morphology of gamma-ray bursts (GRBs) with time duration less than 100 ms that includes: (1) a fast-Fourier spectrum analysis, (2) a comparison with the Stern analysis of longer bursts, (3) an…
Data from the 3B Catalogue suggest that short and long GRB are the results of different classes of events, rather than different parameter values within a single class: Short bursts have harder spectra in the BATSE bands, but chiefly long…
Ultra-long Gamma-Ray Bursts are a class of high energy transients lasting several hours. Their exact nature is still elusive, and several models have been proposed to explain them. Because of the limited coverage of wide field gamma-ray…
Two classes of Gamma Ray Bursts have been identified so far, characterized by T90 durations shorter and longer than approximately 2 seconds. It was shown that the BATSE 3B data allow a good fit with three Gaussian distributions in log T90.…
Several hundred gamma-ray burst (GRB) redshifts have been determined to date. One of the other important properties-besides the distance-of the GRBs is the duration of the burst. In this paper, we analyse these two important quantities of…
We study correlations between various hardness ratios of gamma-ray bursts (GRBs) and investigate if there are any differences between the two classes of the objects in the distributions of the ratios. The results suggest that,…
Before the BATSE/GRO launch GRBs seem to be a uniform phenomenon with duration up to about 100 seconds. The BATSE has detected many events longer than 100 s and a few longer than 500s. We performed the off-line scan of the 1024 ms…