Cosmological tests of theories of gravity beyond General Relativity
Alternative theories of gravity have gathered much attention recently due to 1) their ability to explain the late time accelerated expansion of the Universe; and 2) the mere fact that gravity has never been tested in a robust and model-independent way outside of the Solar System. Studies of alternative theories therefore help to understand how the different cosmological observables can be affected, and hence, improve the quality of our observational tests. In this talk, I will go through a series of steps that one can take to constrain these models. I will use results from the well understood CMB-related linear theory predictions (temperature anisotropies, CMB lensing, ISW effect, etc), but also more targeted tests on nonlinear scales involving the lensing signal around galaxy clusters and cosmic voids. For illustrative purposes, I will focus on two popular models, which are Galileon and Nonlocal gravity, although most of the conclusions will be general to other models.