Constraints from Fermi observations of Long Gamma-Ray Bursts on cosmological parameters

TL;DR

This study uses 15 years of Fermi long gamma-ray burst data with redshifts to calibrate correlations and constrain cosmological parameters, providing more precise results than previous GRB-based studies.

Contribution

It calibrates the Amati relation using Gaussian Process and combines GRB data with supernovae to improve constraints on cosmological models.

Findings

Estimated matter density parameter 0.3541.8

Measured Hubble constant 73.05 km/s/Mpc

Constrained dark energy equation of state parameters

Abstract

In this paper, we compile a \emph{Fermi} sample of the \emph{long} GRB observations from 15 years of GBM catalogue with identified redshift, in which the GOLD sample contains 123 long GRBs at $z\le5.6$ and the FULL sample contains 151 long GRBs with redshifts at $z\le8.2$. The Amati relation (the $E_{\rm p,i}$-$E_{\rm iso}$ correlation) are calibrated at $z<1.4$ by a Gaussian Process from the latest observational Hubble data (OHD) with the cosmic chronometers method so that GRBs at high-redshift $z\ge1.4$ can be used to constrain cosmological models via the Markov chain Monte Carlo (MCMC) method. From the cosmology-independent GRBs with the GOLD sample at $z\ge1.4$ and the Pantheon+ sample of type Ia supernovae (SNe Ia) at $0.01<z\leq2.3$, we obtain $\Omega_{\rm m} = 0.354\pm0.018, H_0 = 73.05\pm0.2\,\rm{km/s/Mpc}$ for the flat $\Lambda$CDM model; $w_0 = -1.22^{+0.18}_{-0.15}$ for the flat $w$CDM model; and $w_{a} = -1.12^{+0.45}_{-0.83}$ for the flat Chevallier-Polarski-Linder model at the 1$\sigma$ confidence level. Our results with the GOLD and FULL sample are almost identical, which are more stringent than the previous results with GRBs.