The Direct Test of Cosmological Model for Cosmic Gamma-Ray Bursts Based on the Peak Alignment Averaging

TL;DR

This study tests the cosmological origin of gamma-ray bursts by analyzing their light curves and finds no evidence supporting the expected cosmological effects, challenging standard models.

Contribution

It introduces a peak alignment averaging method to directly test cosmological models of gamma-ray bursts using BATSE data.

Findings

No evidence for predicted cosmological effects in burst light curves

Estimated redshift upper limit for dim bursts is Z<0.5

Results challenge the standard cosmological models for gamma-ray bursts

Abstract

The cosmological origin of cosmic gamma-ray bursts is tested using the method of peak alignment for the averaging of time profiles. The test is applied to the basic cosmological model with standard sources, which postulates that difference between bright and dim bursts results from different cosmological red-shifts of their sources. The average emissivity curve (ACEbright) of the group of bright BATSE bursts is approximated by a simple analytical function, which takes into account the effect of squeezing of the time pulses with increasing energy of photons. This function is used to build the model light curve for ACEdim of dim BATSE bursts, which takes into account both the cosmological time- stretching of bursts light curves and the red-shifting of photons energies. Direct comparison between the model light curve and the ACEdim of dim bursts is performed, which is based on the estimated probabilities of differences between ACEs of randomly selected groups of bursts. It shows no evidence for the predicted cosmological effects. The 3 sigma upper limit of the average red- shift Zdim of emitters of dim bursts is estimated to be as small, as 0.1-0.5, which is not consistent with values 1 predicted by the known cosmological models of gamma-ray bursts.