Statistical Tests for CHDM and ΛCDM Cosmologies
Abstract
We apply several statistical estimators to highresolution Nbody simulations of two currently viable cosmological models: a mixed dark matter model, having Ω_{ν} = 0.2 contributed by two massive neutrinos (C + 2νDM), and a cold dark matter model with cosmological constant (ΛCDM) with Ω_{0} = 0.3 and h = 0.7. Our aim is to compare simulated galaxy samples with the PerseusPisces redshift survey (PPS). We consider the npoint correlation functions (n = 24) the Ncount probability functions P_{N}, including the void probability function P_{0}; and the underdensity probability function U_{∊} (where ∊ fixes the underdensity threshold in percentage of the average). We find that P_{0} (for which PPS and CfA2 data agree) and P_{1} distinguish efficiently between the models, while U_{∊} is only marginally discriminatory. On the contrary, the reduced skewness and kurtosis are, respectively, S_{3} ~= 2.2 and S_{4} ~= 67 in all cases, quite independent of the scale, in agreement with hierarchical scaling predictions and estimates based on redshift surveys. Among our results, we emphasize the remarkable agreement between PPS data and C + 2νDM in all the tests performed. In contrast, the above ΛCDM model has serious difficulties in reproducing observational data if galaxies and matter overdensities are related in a simple way.
 Publication:

The Astrophysical Journal
 Pub Date:
 April 1997
 DOI:
 10.1086/303912
 arXiv:
 arXiv:astroph/9611103
 Bibcode:
 1997ApJ...479..580G
 Keywords:

 Cosmology: Theory;
 Cosmology: Dark Matter;
 Galaxies: Clusters: General;
 Cosmology: LargeScale Structure of Universe;
 Astrophysics
 EPrint:
 12 pages, 10 figures, LaTeX (aaspp4 macro), in press on ApJ, Vol. 479, April 1997