Astrophysics Seminar

Model-independent constraints on modified gravity models hitherto exist mainly on linear scales. I will present the first N-body simulations of modified gravity models based on a consistent parameterization that is valid on all scales. I investigate the impact of a time-dependent modification of the gravitational force on the matter power spectrum and consequently on weak-lensing observables, with particular focus on the constraining power gained by including non-linear scales. I will describe a fitting function that predicts the non-linear matter power spectrum based on the recently proposed halo model reaction formalism and validate it against my simulations. I will finally conclude on how this pipeline may be implemented in modified gravity/dark energy forecasts for future surveys such as Euclid and the Vera Rubin Telescope (LSST). This paves the way for a full model-independent test of modified gravity using all of the data from such upcoming surveys.