Cosmological constraints on sub-horizon scales modified gravity theories with MGCLASS II

Abstract In this paper we introduce a new public Einstein-Boltzmann solver, MGCLASS II , built as modification of the publicly available CLASS code, that allows to obtain cosmological observables in Modified Gravity theories. It implements several commonly used parameterizations deviations from General Relativity, computing their impact on growth structure well background evolution Universe, together with subset alternative theories, still not completely ruled out by observations. is such way be compatible parameter estimation codes MontePython and Cobaya . We exploit possibility constrain Planck collaboration, order validate predictions newly implemented parameterization (z_flex) which has different features. For former find good agreement results existing literature, while present original constraints parameters latter, finding no significant deviation standard model, ΛCDM.