Speaker: Marco Bruni
Location: Workshop “Theoretical challenges for precision galaxy clustering”, Sexten Center for Astrophysics, Italy
In this talk I will describe progresses in considering GR effects in the dynamics of structure formation. First I will present results of a nonlinear post-Friedman approximation, a kind of post-Newtonian formalism. Then I will focus on recent fully nonlinear numerical relativity simulations. The application of numerical relativity to cosmology is in its infancy, but in the next few years can be a fundamental tool to understand the extent to which we can trust standard newtonian N-body simulations. First results of simulations representing perturbations in a Einstein de Sitter background are: 1) back-reaction effects on the overall expansion of the model are tiny; 2) voids expansion rate is significantly higher than that of the background; 3) over-densities can reach turn-around much earlier than predicted by the standard top-hat model. To establish the significance of these results is the goal of future work, and this can be an interesting topic for discussion at the workshop.