NON-GAUSSIAN INITIAL CONDITIONS IN COSMOLOGICAL N-BODY SIMULATIONS .2. COLD DARK MATTER MODELS

Results are reported on N-body simulations of the large-scale structure of the Universe starting from non-Gaussian initial conditions in a Cold Dark Matter cosmogony. We consider three multiplicative models where the peculiar gravitational potential is obtained by performing a non-linear transformation on a Gaussian random field: while keeping the standard form for the initial power spectrum, this procedure provides highly non-random phases. The resulting distributions in space and velocity are analysed by different statistical tests and compared with the evolution of a standard Gaussian model with the same initial amplitude. We find that both the clustering dynamics and the present texture are mostly sensitive to the sign of the initial skewness of mass fluctuations. In particular, models characterized by a substantial predominance of primordial underdense regions (negative skewness) evolve towards a cellular structure with large correlation length and enhanced peculiar motions. Our results suggest that the Cold Dark Matter scenario can succeed in reproducing structures on large scales if the random-phase hypothesis is abandoned.