Observational constraints on exponential gravity

Abstract

We study the observational constraints on the exponential gravity model of $f(R)=\ensuremath{-}\ensuremath{\beta}{R}_{s}(1\ensuremath{-}{e}^{\ensuremath{-}R/{R}_{s}})$. We use the latest observational data including Supernova Cosmology Project Union2 compilation, Two-Degree Field Galaxy Redshift Survey, Sloan Digital Sky Survey Data Release 7, and Seven-Year Wilkinson Microwave Anisotropy Probe in our analysis. From these observations, we obtain a lower bound on the model parameter $\ensuremath{\beta}$ at 1.27 (95% C.L.) but no appreciable upper bound. The constraint on the present matter density parameter is $0.245<{\ensuremath{\Omega}}_{m}^{0}<0.311$ (95% C.L.). We also find out the best-fit value of model parameters on several cases.