The Effects of Non‐Gaussian Initial Conditions on the Structure and Substructure of Cold Dark Matter Halos

We study the structure and substructure of halos obtained in N-bodysimulations for a Lambda Cold Dark Matter (LCDM) cosmology with non-Gaussianinitial conditions (NGICs). The initial statistics are lognormal in thegravitational potential field with positive (LNp) and negative (LNn) skewness;the sign of the skewness is conserved by the density field, and the powerspectrum is the same for all the simulations. Our aim is not to test a givennon-Gaussian statistics, but to explore the generic effect of positive- andnegative-skew statistics on halo properties. From our low-resolutionsimulations, we find that LNp (LNn) halos are systematically more (less)concentrated than their Gaussian counterparts. This result is confirmed by ourMilky Way- and cluster-sized halos resimulated with high-resolution. Inaddition, they show inner density profiles that depend on the statistics: theinnermost slopes of LNp (LNn) halos are steeper (shallower) than those obtainedfrom the corresponding Gaussian halos. A subhalo population embedded in LNphalos is more susceptible to destruction than its counterpart inside Gaussianhalos. On the other hand, subhalos in LNn halos tend to survive longer thansubhalos in Gaussian halos. The spin parameter probability distribution of LNp(LNn) halos is skewed to smaller (larger) values with respect to the Gaussiancase. Our results show how the statistics of the primordial density field caninfluence some halo properties, opening this the possibility to constrain,although indirectly, the primordial statistics at small scale.Comment: 15 pages, 8 figures. Slight corrections after referee report. To appear in ApJ, v598, November 20, 200