Late-time constraints on Chern–Simons gravity in the Friedmann–Lemaître–Robertson–Walker (FLRW) universe

Our work focuses on the late-time constraints of dynamical Chern–Simons modified gravity (CSMG) theory in the Friedmann–Lemaître–Robertson–Walker (FLRW) universe. We determine which possibilities are physically plausible by examining how well the model fits the data. We challenge the cosmological model using the most current observational evidence, specifically the Supernovae type Ia (SN Ia), Observational Hubble data (OHD), Baryonic acoustic oscillations (BAO) and cosmic microwave background (CMB) observations. The [Formula: see text]-minimization technique is used to constrain the model parameters. In addition, we pick our model using the Bayesian Information Criterion (BIC) and the Akaike Information Criterion (AIC), and we compare it to the [Formula: see text]CDM model, which is our reference. The evolution of the effective equation of state (EoS) parameter, deceleration parameter (DP), and cosmographic parameters (CP) is thoroughly explored using the model parameters’ best fit values. These observational data sets indicate a strong agreement between the theoretical model and the observations. The dynamical behavior of DP explains the shift for the CSMG Universe from a decelerated to an accelerated expanding phase. In the distant future, the universe will approach the [Formula: see text] cold dark matter ([Formula: see text]CDM) model in terms of best fit values for model parameters.