Laura Taddei (ITP Heidelberg, Germany)
Most cosmological constraints on modified gravity are obtained assuming that the cosmic evolution was standard CDM in the past and that the present matter density and power spectrum normalization are the same as in a CDM model. Here we examine how the constraints change when these assumptions are lifted. We focus in particular on the parameter Y (also called G_effective ) that quanties the deviation from the Poisson equation. We obtain constraints on this parameter by using current RSD measurements combined with the measurements of the apparent magnitude of the Sn Ia, taken from the JLA catalogue. We also forecast the precision of a future estimation of Y for a Euclid-like redshift survey and for a SKA1 and SKA2 mission. We produce a forecast of a cosmological exclusion plot on the Yukawa strength and range parameters, which complements similar plots on laboratory scales but explores scales and epochs reachable only with large-scale galaxy surveys.