Constraining cosmological parameters by Gamma Ray Burst X - ray afterglow lightcurves

TL;DR

This paper constructs a Hubble diagram from 66 Gamma Ray Bursts' X-ray afterglow data to constrain cosmological parameters, demonstrating consistency with previous results and emphasizing the potential of larger GRB samples for cosmology.

Contribution

It introduces a new method to derive a GRB-based Hubble diagram using the L_X - T_a correlation, aiding cosmological parameter estimation.

Findings

GRBs provide constraints consistent with previous cosmological studies.

The X-ray afterglow data can be effectively used for cosmology.

Larger high-luminosity GRB samples can improve cosmological model testing.

Abstract

We present the Hubble diagram (HD) of 66 Gamma Ray Bursts (GRBs) derived using only data from their X - ray afterglow lightcurve. To this end, we use the recently updated L_X - T_a correlation between the break time T_a and the X - ray luminosity L_X measured at T_a calibrated from a sample of Swift GRBs with lightcurves well fitted by the Willingale et al. (2007) model. We then investigate the use of this HD to constrain cosmological parameters when used alone or in combination with other data showing that the use of GRBs leads to constraints in agreement with previous results in literature. We finally argue that a larger sample of high luminosity GRBs can provide a valuable information in the search for the correct cosmological model.