Observational constraints on EoS parameters of various modified Chaplygin gas models

Cosmological models of a class of modified Chaplygin gas as a candidate of unified dark matter and energy are studied to determine observational constraints on its EoS parameters using the background data. These data consist of $H\left(z\right)-z$ (OHD) data, baryonic acoustic oscillations peak parameter data, CMB shift parameter and SN Ia (Union 2.1) data. Best-fit value of present Hubble parameter ($H_0$), present matter density (${\Omega }_{m0}$) and present age of the Universe ($t_0$) has been determined in all these models. The acceptable range of values of the EoS parameters is determined in the analysis. Variations of EoS parameter ($\omega$), squared sound speed ($c_s^2$) and deceleration parameter (q) with redshift are also studied here. Akaike information criteria and Bayesian information criterion are used to check the suitability of the models. Density perturbation and CMB temperature anisotropy have also been studied.