Modified Chaplygin gas and constraints on its B parameter from cold dark matter and unified dark matter energy cosmological models

We study modified Chaplygin gas (MCG) as a candidate for dark energy and predict the values of parameters of the gas for a physically viable cosmological model. The equation of state of MCG     involves three parameters: B , A and α. The permitted values of these parameters are determined with the help of a dimensionless age parameter  ( H ₀ t ₀)  and   H ( z ) ? z   data. Specifically, we study the allowed ranges of values of the B parameter in terms of α and   A_s   (   A_s   is defined in terms of the parameters in the theory). We explore the constraints of the parameters in the cold dark matter and unified dark matter energy models, respectively.