Reconciliation of the Disparate Gamma-Ray Burst Catalogs in the Context of a Cosmological Source Distribution

Abstract

It is well-known that gamma-ray burst spectra often display a break at energies ≤400 keV, with some exceptions extending to several MeV. Modeling of a cosmological source population is thus nontrivial when comparing the catalogs from instruments with different energy windows since this spectral structure is redshifted across the trigger channels at varying levels of sensitivity. We here include this important effect in an attempt to reconcile all the available data sets and show that a model in which bursts have a standard spectral break at 300 keV and occur in a population uniformly distributed in a q 0 =1/2 universe with no evolution can account very well for the combined set of observations