Luminosity function of BATSE GRBs whose prompt emission is not dominated by the P-GRB

Abstract

A statistical analysis has been done by Schmidt (2009) [1] on the GRB prompt emission data of the GUSBAD catalog (Schmidt 2004 [2]), where a collection of sources from the BATSE detector were selected. In this analysis is assumed that GRBs are described by five different Gaussian luminosity functions, which correspond to five spectral classes obtained from the four channels of the BATSE detector. A GRB sample with redshift from Swift is used to calibrate the luminosity function. It is also used the Euclidean value of V /V max as a cosmological distance indicator, since GUSBAD sources do not have measured redshift. A correlation V /V max vs E ob pk , and then L iso vs E pk , is obtained. It is also found the Malmquist bias for GRBs with lower energy, because they are not detected for large redshifts. In the Fireshell model, GRB prompt emission is formed by two phases each one due to a particular physical process: the P-GRB and the extended afterglow peak (Ruffini et al. 2009 [3]). The first one is produced at the fireshell transparency, the second by the subsequent interaction between the optically thin fireshell and the circumburst medium (CBM). We therefore repeated the same statistical analysis of Schmidt (2009) [1], but with two main differences; in the first, we used a "sanitized" GUSBAD sample, excluding GRBs whose prompt emission is dominated by the P-GRB emission; and in the second, the GRB rate density obtained by Wanderman & Piran (2010) [4] is used, instead of that obtained by Schmidt (2009).