Non-Gaussian Initial Conditions in Cosmological N-body Simulations: III. Groups in Cold Dark Matter Models

This study presents group catalogs in N-body simulations of the large-scale structure of the universe with non-Gaussian initial conditions in a Cold Dark Matter cosmogony. Groups of particles are defined by the standard percolation algorithm with linking parameter b of 0.25 in units of the mean interparticle distances. Grouping particles are found to strongly depend on the statistics of the underlying mass distribution. An analysis is made of the clustering and the topology of the group distribution, the environmental properties of the groups, and their internal geometric and dynamical features. Groups in negative models, i.e., models characterized by a predominance of primordial underdense regions, are preferentially loose systems, slightly biased over the background, with high velocity dispersion and clear signal alignment with neighboring groups up to about 30/sq h Mpc. Groups in positive models, i.e., models with a predominance of primordial overdense regions, are highly biased compact systems with lower velocity dispersion.