On the statistical analyses of the cosmic velocity field

Many statistical analyses of the cosmic velocity held are based on the gala xy number-weighted sampling and therefore cannot escape from the bias effec t. We study this problem in the framework of the stochastic bias mechanism using a simplified model and the results of a recent hydrodynamical simulat ion. We adopt the velocity correlation functions as representative examples and show that velocity statistics might be qualitatively affected by the p oorly understood bias mechanism and strongly depend on the tracers of the c osmic velocity field.