Observational constraints on cosmological parameters in the Bianchi type III Universe with f(R,T) gravity theory

TL;DR

This study explores the Bianchi type III universe within $f(R,T)$ gravity, estimating cosmological parameters using observational data, and finds that while models align with current observations, they show deviations in early cosmic stages.

Contribution

The paper applies $f(R,T)$ gravity to Bianchi type III models and evaluates their cosmological parameters with Bayesian methods, highlighting limitations in early universe modeling.

Findings

Models are consistent with current observations.

Deviations occur in the early universe stages.

One model shows a sharp discontinuity during radiation era.

Abstract

Bianchi type III (BIII) metric is an interesting anisotropic model for studying cosmic anisotropy as it has an additional exponential term multiplied to a directional scale factor. Thus, the cosmological parameters obtained for this BIII metric with the conventional energy-momentum tensor within the framework of a modified gravity theory and the estimation of their values with the help of Hubble, Pantheon plus and other observational data may provide some new information in cosmic evolution. In this work, we have studied the BIII metric under the framework of $f(R,T)$ gravity theory and estimated the values of the cosmological parameters for three different models of this gravity theory by using the Bayesian technique. In our study, we found that all the models show consistent results with the current observations but show deviations in the early stage of the Universe. In one model we have found a sharp discontinuity in the radiation-dominated phase of the Universe. Hence through this study, we have found that all the $f(R,T)$ gravity models may not be suitable for studying evolutions and early stages of the Universe in the BIII metric even though they show consistent results with the current observations.