A DIRECT TEST OF THE COSMOLOGICAL MODEL FOR COSMIC GAMMA-RAY BURSTS BASED ON PEAK ALIGNMENT AVERAGING

The cosmological origin of cosmic gamma-ray bursts is tested by using the method of peak alignment for the averaging of time profiles. The t est is applied to the basic cosmological model with standard sources, which postulates that the difference between bright and dim bursts res ults from the different cosmological redshifts of their sources. The a verage emissivity curve (ACE(bright)) of a group of bright BATSE burst s is approximated by a simple analytic function that takes into accoun t the effect of the squeezing of the time pulses with increasing energ y of photons. This function is used to build the model light curve for ACE(dim) of dim BATSE bursts, which takes into account both the cosmo logical time-stretching of the light curves of bursts and the redshift ing of photon energies. Direct comparison between the model light curv e and the ACE(dim) of dim bursts is performed, based on the estimated probabilities of differences between ACEs of randomly selected groups of bursts. The comparison shows no evidence for the predicted cosmolog ical effects. The 3 a upper limit of the average redshift z(dim) of em itters of dim bursts is estimated to be as small as similar to 0.1-0.5 , which is not consistent with values of similar to 1 predicted by cur rent cosmological models of gamma-ray bursts.