Constraints on the generalized Chaplygin gas model including gamma-ray bursts via a Markov Chain Monte Carlo approach

TL;DR

This paper uses a Markov Chain Monte Carlo approach to combine gamma-ray burst data with other cosmological observations, providing tighter constraints on the generalized Chaplygin gas model parameters than previous studies.

Contribution

It introduces a comprehensive MCMC analysis incorporating high-redshift GRB data to improve constraints on the GCG model parameters.

Findings

Best-fit GCG parameters are A_S=0.7475, α=-0.0256, Ω_m=0.2629.

Constraints are more stringent than previous results.

The analysis combines SNe Ia, CMB, BAO, and GRB data.

Abstract

We investigate observational constraints on the generalized Chaplygin gas (GCG) model including the gamma-ray bursts (GRBs) at high redshift obtained directly from the Union2 type Ia supernovae (SNe Ia) set. By using the Markov Chain Monte Carlo method, we constrain the GCG model with the cosmology-independent GRBs, as well as the Union2 set, the cosmic microwave background (CMB) observation from the Wilkinson Microwave Anisotropy Probe (WMAP7) result, and the baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample. The best-fit values of the GCG model parameters are $A_S$=$0.7475_{-0.0539}^{+0.0556}(1\sigma)_{-0.0816}^{+0.0794}(2\sigma)$, $\alpha$=$-0.0256_{-0.1326}^{+0.1760}(1\sigma)_{-0.1907}^{+0.2730}(2\sigma)$, and the effective matter density $\Omega_{m}=0.2629_{-0.0153}^{+0.0155}(1\sigma)_{-0.0223}^{+0.0236}(2\sigma)$, which are more stringent than the previous results for constraining on GCG model parameters.