Friedmann-Robertson-Walker Models with Late-Time Acceleration

TL;DR

This paper proposes a modified FRW cosmological model with a new density variation ansatz that results in a variable Chaplygin gas equation of state, explaining late-time cosmic acceleration.

Contribution

It introduces a novel modification to the FRW model's density variation, linking it to a variable Chaplygin gas to account for acceleration.

Findings

The modified ansatz yields an equation of state consistent with late-time acceleration.

The model reduces to MGCG and CG during evolution.

It provides a theoretical framework for cosmic acceleration without dark energy.

Abstract

In order to account for the observed cosmic acceleration, a modification of the ansatz for the variation of density in Friedman-Robertson-Walker (FRW) models given by Islam is proposed. The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that of a modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.