Are gamma-ray bursts cosmological?

TL;DR

This paper investigates whether gamma-ray bursts are of cosmological origin by analyzing their brightness distribution and spatial isotropy, finding that cosmological models fit the data well within reasonable parameters.

Contribution

It provides detailed fits of gamma-ray burst brightness distributions with Friedmann models, considering density evolution and luminosity functions, and assesses their compatibility with cosmological origins.

Findings

Cosmological models fit the gamma-ray burst data well.

Brightness distribution supports a cosmological origin.

Density evolution and luminosity parameters are constrained.

Abstract

Gamma-ray burst sources are distributed with a high level of isotropy, which is compatible with either a cosmological origin or an extended Galactic halo origin. The brightness distribution is another indicator used to characterize the spatial distribution in distance. In this paper the author discusses detailed fits of the BATSE gamma-ray burst peak-flux distributions with Friedmann models taking into account possible density evolution and standard candle luminosity functions. A chi-square analysis is used to estimate the goodness of the fits and the author derives the significance level of limits on the density evolution and luminosity function parameters. Cosmological models provide a good fit over a range of parameter space which is physically reasonable