Angular two-point correlation functions for cosmological gamma-ray burst model

Abstract

We compute the angular two-point correlation functions of the gamma-ray bursts at cosmological distances. Since the gamma-ray burst emission mechanism is not yet established, we simply assume that the gamma-ray burst sources are associated with high-redshift galaxies in some way. Then on the basis of several simple models for the evolution of galaxy spatial correlations, we calculate the amplitude of angular two-point correlation functions on scales appropriate for the Compton Gamma Ray Observatory data. we find that in most cases the predicted correlations are difficult to detect with the current data rate and the angular resolution, but models in which the bursts preferentially occur at relatively low redshift ($z \simlt 0.5$) predict correlation amplitudes on $θ\sim 5^\circ$ which will be marginally detectable with the Gamma Ray Observatory data in several years. If future observations detect a signal of angular correlations, it will imply useful information on the correlation of galaxies at high redshifts provided that the gamma-ray bursts are cosmological.