Cosmic structure formation in massive conformal gravity

Abstract

We study the evolution of matter density perturbations in the framework of massive conformal gravity (MCG). Starting from the conservation of the energy-momentum tensor, we find the continuity and Euler equations for the conformal perfect fluid that fills the MCG universe. We then obtain the perturbed MCG cosmological equations, from which we derive the equation that determines the linear growth of matter fluctuations in the MCG universe. The resulting growth equation shows that MCG enhances cosmic structure formation at high redshifts and suppresses it at low redshifts when compared to the $\Lambda$CDM cosmological model.