Constraints on modified Chaplygin gas from recent observations and a comparison of its status with other models

In this Letter, a modified Chaplygin gas (MCG) model of unifying dark energy and dark matter with the exotic equation of state pMCG=BρMCG−AρMCGα is constrained from recently observed data: the 182 Gold SNe Ia, the 3-year WMAP and the SDSS baryon acoustic peak. It is shown that the best fit value of the three parameters (B,Bs,α) in MCG model are (−0.085,0.822,1.724). Furthermore, we find the best fit w(z) crosses −1 in the past and the present best fit value w(0)=−1.114<−1, and the 1σ confidence level of w(0) is −0.946⩽w(0)⩽−1.282. Finally, we find that the MCG model has the smallest χmin2 value in all eight given models. According to the Akaike Information Criterion (AIC) of model selection, we conclude that recent observational data support the MCG model as well as other popular models.