Cosmological Probes of Screening Mechanisms in Modified Gravity
Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms intended to hide the scalar field below observational limits in the solar system, but not on galactic scales, where data still gives freedom to find possible signatures of their presence. I describe how one can use structure formation to study screening mechanisms in extensions to General Relativity. In particular, I will present observable signatures of modified gravity in the nonlinear matter power spectrum, on the halo mass function and other properties of galaxy clusters. Those would help us to discriminate between models with and without scalar fields and even between different screening mechanisms.