Observational constraints on EoS parameters of emergent universe

Abstract

We investigate emergent universe model using recent observational data of the background as well as the growth tests. The flat emergent universe model obtained by Mukherjee et al. is permitted with a non-linear equation of state (in short, EoS) ( $p=A\rho -B \rho^{\frac{1}{2}}$ ), where $A$ and $B$ are constants (here in our analysis $A=0$ is considered). We carried out analysis considering the Wang–Steinhardt ansatz for growth index ( $\gamma $ ) and growth function ( $f$ defined as $f=\varOmega_{m}^{\gamma } (a)$ ). The best-fit values of the EoS and growth parameters are determined making use of $chi$ -square minimization technique. Here we specifically determined the best-fit value and the range of value of the present matter density ( $\varOmega _{m}$ ) and Hubble parameter ( $H_{0}$ ). The best-fit values of the EoS parameters are used to study the evolution of the growth function $f$ , growth index $\gamma $ , state parameter $\omega $ and deceleration parameter ( $q$ ) for different red shift parameter $z$ . The late accelerating phase of the universe in the EU model is accommodated satisfactorily.