Generalized Chaplygin gas model: constraints from Hubble parameter versus Redshift Data

TL;DR

This paper constrains the generalized Chaplygin gas model using observational data from Hubble parameter measurements, supernovae, and baryonic acoustic oscillations, finding that certain parameter ranges are viable while the standard model is ruled out.

Contribution

It provides the first combined observational constraints on the GCG model parameters using multiple cosmological data sets.

Findings

Allowed parameter range for $A_s$ and $\alpha$ within GCG model.

Standard Chaplygin gas ($\alpha=1$) is ruled out at 99.7% confidence.

GCG remains a viable candidate for unified dark matter and dark energy.

Abstract

We examine observational constraints on the generalized Chaplygin gas (GCG) model for dark energy from the 9 Hubble parameter data points, the 115 SNLS Sne Ia data and the size of baryonic acoustic oscillation peak at redshift, $z=0.35$. At a 95.4% confidence level, a combination of three data sets gives $0.67\leq A_s\leq 0.83$ and $-0.21\leq \alpha\leq 0.42$, which is within the allowed parameters ranges of the GCG as a candidate of the unified dark matter and dark energy. It is found that the standard Chaplygin gas model ($\alpha=1$) is ruled out by these data at the 99.7% confidence level.