Redshift distribution of gamma-ray bursts and star formation rate

Abstract

Aims.The redshift distribution of gamma-ray bursts collected in the BATSE Catalog is compared with the star formation rate. We aim to clarify the accordance between them. We also study the case of comoving number density of bursts monotonously increasing up to redshift ≃ (6-20). Methods: .A method independent of the models of the gamma-ray bursts is used. The short and the long subgroups are studied separately. Results: .The redshift distribution of the long bursts may be proportional to the star formation rate. For the short bursts this can also happen, but the proportionality is less evident. For the long bursts the monotonously increasing scenario is also less probable but still can occur. For the short bursts this alternative seems to be excluded.