Numerical Analyses of Weakly Nonlinear Velocity-Density Coupling

Abstract

We study evolution of various statistical quantities of smoothed cosmic density and velocity fields using N-body simulations. The parameter $C\equiv <V^2\delta >/(<V^2><{\delta }^2>)$ characterizes nonlinear coupling of these two fields and determines behavior of bulk velocity dispersion as a function of local density contrast. It is found that this parameter depends strongly on the smoothing scale even in quasi-linear regimes where the skewness parameter $S_3$ is nearly constant and close to the predicted value by the second-order perturbation theory. We also analyze weakly nonlinear effects caused by an adaptive smoothing known as the gather approach.

22 pages, 4 figures, to appear in ApJ (558, Sep 10)

Cited by in corpus (1)

• Numerical study of the cosmological velocity field as a function of density