Observational constraints on a transit cosmological model in f(R, G) gravity

In this article, we examine the universe's dynamical behaviour in the context of the f(R, G) theory of gravity, where R and G represent the Ricci scalar and Gauss-Bonnet invariant, respectively. The modified field equations are solved for the selection of f(R, G) function as f(R, G) = R(beta)G1-(beta) and of the deceleration parameter as a linear function of Hubble parameter, i.e., q = n+ mH. We predict the best fit values of model parameters that would be in agreement with the recent observational datasets. We use the CC, Pantheon and BAO datasets as well as the Bayesian analysis and likelihood function together with the MCMC method. Further, we examine the physical behavior of cosmographic parameters corresponding to the constrained values of the model parameters as well as the energy density and pressure. The model obtained exhibits a transition from decelerating to accelerating expansion phases of the universe. We show that our f(R, G) model can explain the late accelerating expansion of the universe without calling any dark energy term in the energy-momentum tensor.

Automated summary

In this article, the dynamical behavior of the universe is examined in the context of the f(R, G) theory of gravity, which incorporates the Ricci scalar and Gauss-Bonnet invariant. The best fit values of model parameters are predicted to be in agreement with recent observational datasets, using the CC, Pantheon and BAO datasets, Bayesian analysis, likelihood function, and MCMC method. The obtained f(R, G) model exhibits a transition from decelerating to accelerating expansion of the universe, explaining the late accelerating expansion without the need for dark energy.