Searching for Constraints on Starobinsky’s Model with a Disappearing Cosmological Constant on Galaxy Cluster Scales

Abstract

Predictions of the f(R)-gravity model with a disappearing cosmological constant (Starobinsky’s model) on scales characteristic of galaxies and their clusters are considered. The absence of a difference in the mass dependence of the turnaround radius between Starobinsky’s model and General Relativity accessible to observation at the current accuracy of measurements has been established. This is true both for small masses (from 10⁹M_Sun) corresponding to an individual galaxy and for masses corresponding to large galaxy clusters (up to 10¹⁵M_Sun). The turnaround radius increases with parameter n for all masses. Despite the fact that some models give a considerably smaller turnaround radius than does General Relativity, none of the models goes beyond the bounds specified by the observational data.