Effect of the Modified Gravity on the Large-scale Structure Formation

Abstract

We investigate the formation of the large-scale structures in the present accelerated era in the f(R) gravity background. This is done by considering the linear growth of matter perturbations at low redshift z < 1. The effect of f(R) alters the behavior of the matter density perturbations from the matter-dominated universe to the late-time accelerated universe, which is encoded in the Newtonian gravitational constant as G → G eff. The modified gravitational constant (G eff) depends on the form of f(R). The late-time accelerated expansion affects the formation of large-scale structures by slowing down the growth of matter density. On the other hand, f(R) increases the growth rate of the matter density perturbations. We have found that the source term in the f(R) background, G effΩ m , overcomes the accelerated expansion and the effect of accelerated expansion suppresses the formation of the large-scale structures in the asymptotic future.