Large-Scale Density--Velocity Relations

Abstract

I present recent progress in theoretical modelling of cosmological density--velocity relations in the weakly nonlinear regime. The relations are local, based on rigorous perturbation theory and include the effects of smoothing of the density and the velocity fields. For small smoothing scales, they can be improved by slight adjustments based on N-body results. The relations can be useful for density--velocity comparisons, yielding a fair estimate of Omega and offering a method for disentangling Omega and bias.