TESTS FOR COALESCING BINARY NEUTRON-STARS AS COSMOLOGICAL ORIGIN OF GAMMA-RAY BURSTS

Theoretical log N-log S distributions and [V/V-max] tests of gamma-ray bursts in the model of coalescence of neutron star (NS+NS) and/or NS + black hole (NS+BH) binaries are calculated for a flat Universe (Omeg a = 1) with different values of the cosmological constant Lambda and u nder various assumptions about the star formation history. The observe d log N-log S distribution and value of [V/V-max] = 0.33 for 411 burst s with known C-max/C-lim from the 2d BATSE catalogue are best fitted w ith a model for which Omega(Lambda) = 0.2 and primary star formation o ccurs at redshifts z similar or equal to 5-6.