Observational constraints on modified Chaplygin gas from cosmic growth

Abstract

We investigate the linear growth function for the large scale structures of the universe considering modified Chaplygin gas as dark energy. Taking into account observational growth data for a given range of redshift from the Wiggle-Z measurements and rms mass fluctuations from Ly-α measurements we numerically analyze cosmological models to constrain the parameters of the MCG. The observational data of Hubble parameter with redshift z is also considered. The Wang-Steinhardt ansatz for growth index γ and growth function f (defined as f = Ωmγ(a)) are considered for the numerical analysis. The best-fit values of the equation of state parameters obtained here is employed to study the growth function (f), growth index (γ) and equation of state (ω) with redshift z. The observational constraints on MCG parameters obtained here are compared with that of the GCG model for viable cosmology. It is noted that MCG also satisfactorily accommodates an accelerating phase followed by a matter dominated phase of the universe.