A cosmological model in f (G, T ) gravity with time varying deceleration parameter

The current study aims to investigate a modified theory of gravity called f (G, T) theory. Our focus is on a Gauss-Bonnet cosmolog-ical model that integrates a non-linear Gauss-Bonnet term and a linear trace term. The specific expression of the f (G, T) theory is f (G, T) = G + mG 2 + nT , where m and n represent free parameters. To solve the field equation, we employ a specialized formulation of the deceleration parameter, represented as q = α − β H , where α and β are model parameters. Consequently, we determine the optimal values of the model parameters by aligning them with the latest observational datasets, including 57 data points from the Cosmic Chronometers datasets, Pantheon datasets, and BAO datasets. Furthermore, we analyze the physical behavior of cosmo-graphic parameters corresponding to the constrained values of the model parameters, as well as energy density and pressure. The evolution of the deceleration parameter predicts a transition from decelerated to accelerated phases of the Universe. Importantly, our f (G, T) cosmological model effectively describes the observed cosmic acceleration in the late-time universe, eliminating the need to introduce a dark energy component in the field equations.