Density and velocity fields around clusters of galaxies

We explore the averaged density and infall velocity profiles around clusters of galaxies in several cosmological scenarios. The analysis is based on the statistics of peaks in random Gaussian fields and the spherical infall model. Our method is shown to give accurate predictions for the cluster-galaxy cross-correlation function, and useful predictions for the average infall velocity. The predictions for the cross-correlation function on large scales are very different for models with much power on large scales and models (like Cold Dark Matter) with relatively little power on large scales. The average infall velocity as function of radius is shown to discriminate well between models with different levels of biasing of the galaxy number density fluctuations relative to the mass fluctuations. (orig.)