The spatial distribution of GRBs

Abstract

We analysed the different aspects of the spatial distribution of 542 Gamma-Ray Bursts with precisely determined positions and spectroscopic redshifts. The data were divided according to the origin of the redshift (afterglow or host galaxy). The yearly rate of afterglow and host-based redshift observations are different, with only a few host observations in the recent years. Since the launch of the Swift, the rate of afterglow observations fall exponentially by 50 % in 15 years, potentially affecting all planned GRB missions. We also analysed the rest-frame T90 values from the Swift BAT and FERMI GBM catalogues with the redshift data. The host- and afterglow-based points are separated in the redshift range due to observational effects, but no direct distinction could be made between the rest-frame T90 values. The correlation analysis between the GRB redshift and sky position shows that the GRB distribution could be factorised into a separate sky and radial components.