Session R3: Invited Session: Testing Gravity on Cosmic Scales

Astrophysical Tests of Gravity

Gravity theories designed to explain cosmic acceleration have been actively pursued in recent years. In parallel, large-scale cosmological tests have been formulated and some constraints from observations have already been obtained. This talk will focus on a powerful, new arena for astrophysical tests of gravity: galaxies and stars in the nearby universe. We will argue that scalar-tensor gravity theories generically lead to a wide range of observational signatures that are detectable in nearby galaxies. Observational constraints from existing data within 10-100 Mpc will be presented.   

N-body simulations of modified gravity models

N-body simulations have become an essential tool in cosmology, allowing for quantitative predictions of large-scale structure observables and hence greatly increasing the range of scales that can be used to test the underlying cosmological paradigm. I will present techniques and results of N-body simulations of the f(R) and DGP modified gravity models, which self-consistently take into account the non-linear screening mechanisms contained in these models. The screening mechanisms are essential to allow these models to pass Solar System constraints on gravity, and become relevant in the non-linear regime of large-scale structure.