Speaker
Description
Gamma-ray bursts (GRBs) are the most luminous explosive transients in the cosmos. Generally, long GRBs (LGRBs) with durations $T_{90}$>2s are believed to be powered by the core collapse of massive stars then thus suggested to be excellent tools to probe the star formation rate (SFR) at high redshifts. However, base on the studies over the last two decades, there is a general agreement on the fact that GRBs may have experienced some kind of evolution with redshift. It should be emphasized that the evolution features of GRBs are inferred from the statistics of the observational samples. However, as is well known, the observational samples inevitably subject to various instrumental selection effects and observational biases e.g. trigger problems of faint bursts and redshift-measurement problems for hard location and limited ability of instrument. It is difficult to reveal the intrinsic distributions of long GRBs and their evolution features from these samples. Though some complete samples can provide a solid basis for the statistical study of the long-GRB population, their current sample size is admittedly small. In this work, we update and enlarge the GRB sample observed by Swift/BAT and use it to revisit the GRB luminosity function (LF) and redshift distribution by carefully considering the incomplete sampling of the faint bursts and the probability of redshift measurement.
