A New Class of Bianchi Type-I Cosmological Models in Scalar-Tensor Theory of Gravitation and Late Time Acceleration

TL;DR

This paper introduces new anisotropic Bianchi type-I cosmological models within scalar-tensor gravity that exhibit a transition from deceleration to acceleration, aligning with recent observational data.

Contribution

It presents exact solutions for a new class of anisotropic cosmological models with time-dependent deceleration parameters in scalar-tensor theory.

Findings

Models successfully describe transition from deceleration to acceleration.

Solutions are consistent with recent cosmological observations.

Models include isotropic inflationary phases.

Abstract

A new class of a spatially homogeneous and anisotropic Bianchi type-I cosmological models of the universe for perfect fluid distribution within the framework of scalar-tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett. 113:467, 1986) is investigated. To prevail the deterministic solutions we choose the different scale factors which yield time-dependent deceleration parameters (DP) representing models which generate a transition of the universe from the early decelerated phase to the recent accelerating phase. Three different physically viable models of the universe are obtained in which their anisotropic solutions may enter to some isotropic inflationary era. The modified Einstein's field equations are solved exactly and the models are found to be in good concordance with recent observations. Some physical and geometric properties of the models are also discussed.