Observational constraints on new generalized Chaplygin gas model

TL;DR

This paper uses recent observational data to constrain the parameters of the new generalized Chaplygin gas model, finding a slight preference for a phantom-like dark energy and energy transfer from dark matter to dark energy.

Contribution

It provides the first comprehensive observational constraints on the NGCG model using multiple cosmological data sets.

Findings

Constraints favor a phantom dark energy model.

Energy transfer from dark matter to dark energy is slightly more probable.

Parameters are tightly constrained with 1- and 2-sigma confidence levels.

Abstract

We use the latest data to investigate observational constraints on the new generalized Chaplygin gas (NGCG) model. Using the Markov Chain Monte Carlo (MCMC) method, we constrain the NGCG model with the type Ia supernovae (SNe Ia) from Union2 set (557 data), the usual baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample, the cosmic microwave background (CMB) observation from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) results, the newly revised $H(z)$ data, as well as a value of $\theta_{BAO} (z=0.55) = (3.90 \pm 0.38)^{\circ}$ for the angular BAO scale. The constraint results for NGCG model are $\omega_X = -1.0510_{-0.1685}^{+0.1563}(1\sigma)_{-0.2398}^{+0.2226}(2\sigma)$, $\eta = 1.0117_{-0.0502}^{+0.0469}(1\sigma)_{-0.0716}^{+0.0693}(2\sigma)$, and $\Omega_X = 0.7297_{-0.0276}^{+0.0229}(1\sigma)_{-0.0402}^{+0.0329}(2\sigma)$, which give a rather stringent constraint. From the results, we can see a phantom model is slightly favored and the probability that energy transfers from dark matter to dark energy is a little larger than the inverse.