$E_{\mathrm{iso}}$-$E_{\mathrm{p}}$ correlation of gamma ray bursts: calibration and cosmological applications

TL;DR

This study compiles a large sample of gamma-ray bursts to calibrate the $E_{iso}$-$E_{p}$ correlation, investigates its redshift evolution, and applies it to constrain dark energy properties in the universe.

Contribution

It provides a comprehensive calibration of the $E_{iso}$-$E_{p}$ correlation using a large GRB sample and explores its implications for dark energy evolution.

Findings

No significant redshift evolution of the correlation.

Dark energy EOS may oscillate at low redshift.

Evidence for dynamical dark energy at 2σ confidence level.

Abstract

Gamma-ray bursts (GRBs) are the most explosive phenomena and can be used to study the expansion of Universe. In this paper, we compile a long GRB sample for the $E_{\mathrm{iso}}$-$E_{\mathrm{p}}$ correlation from Swift and Fermi observations. The sample contains 221 long GRBs with redshifts from 0.03 to 8.20. From the analysis of data in different redshift intervals, we find no statistically significant evidence for the redshift evolution of this correlation. Then we calibrate the correlation in six sub-samples and use the calibrated one to constrain cosmological parameters. Employing a piece-wise approach, we study the redshift evolution of dark energy equation of state (EOS), and find that the EOS tends to be oscillating at low redshift, but consistent with $-1$ at high redshift. It hints a dynamical dark energy at $2\sigma$ confidence level at low redshift.