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-$\alpha$ 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 $\gamma$ and growth function $f$ (defined as $f=\Omega_{m}^{\gamma} (a)$) 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 ($\gamma$) and state parameter ($\omega$) with redshift $z$. We note that MCG satisfactorily accommodates an accelerating phase followed by a matter dominated universe.