Population Synthesis of the GRB Progenitors and their Brightness and Redshift Distribution

We estimate the relativistic binaries merger rate and redshift distribution population synthesis of an ensemble of evolving close binaries. Results of such simulations definitely depend on the cosmic star formation rate history, which is different in galaxies of different types. This leads to a difference in merger rate in spiral and elliptical galaxies, which in principle can be an observational test for GRB models. Also a fit of BATSE long bursts \lns is performed, showing that only a wide (2-3 orders of magnitude) luminosity function provides a good fit.