Constraints on Exotic Matter for An Emergent Universe

TL;DR

This paper investigates the parameter constraints for an emergent universe model with exotic matter, using observational data to determine viable ranges for the model's parameters and assess its consistency with cosmological observations.

Contribution

It introduces a specific EOS for exotic matter in emergent universe models and constrains its parameters using observational data, demonstrating the model's viability.

Findings

Most observations favor a small negative A parameter.

The effective EOS remains negative throughout the evolution.

The model is consistent with current cosmological data.

Abstract

We study a composition of normal and exotic matter which is required for a flat Emergent Universe scenario permitted by the equation of state (EOS)($p=A\rho-B\rho^{1/2}$) and predict the range of the permissible values for the parameters $A$ and $B$ to explore a physically viable cosmological model. The permitted values of the parameters are determined taking into account the $H(z)-z$ data obtained from observations, a model independent BAO peak parameter and CMB shift parameter (WMAP7 data). It is found that although $A$ can be very close to zero, most of the observations favours a small and negative $A$. As a consequence, the effective Equation of State parameter for this class of Emergent Universe solutions remains negative always. We also compared the magnitude ($\mu (z)$) vs. redshift($z$) curve obtained in the model with that obtained from the union compilation data. According to our analysis the class of Emergent Universe solutions considered here is not ruled out by the observations.