Are Gamma-Ray Bursts Standard Candles?

TL;DR

This study investigates whether gamma-ray bursts can serve as standard candles by analyzing their spectral relations across different redshift groups, finding significant evolution that challenges their use as standard candles.

Contribution

The paper provides evidence that gamma-ray bursts evolve with redshift, indicating they are not reliable standard candles for cosmological measurements.

Findings

Parameters a and b vary systematically with redshift

GRBs show strong evolution with cosmic redshift

GRBs are not suitable as standard candles

Abstract

By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four groups with redshift from low to high and fitting each group with the Amati relation log Eiso = a + b log Epeak, I find that parameters a and b vary with the mean redshift of the GRBs in each group systematically and significantly. The results suggest that GRBs evolve strongly with the cosmic redshift and hence are not standard candles.