%0 Journal Article
%T Correlation Between the Halo Concentration (c) and the Virial Mass (Mvir) Determined from X-ray Clusters
%A Xiang-Ping Wu
%A Yan-Jie Xue
%J Physics
%D 1999
%I arXiv
%R 10.1086/312451
%X Numerical simulations of structure formation have suggested that there exists a good correlation between the halo concentration c (or the characteristic density delta_c) and the virial mass Mvir for any virialized dark halo described by the Navarro, Frenk & White (1995) density profile. In this Letter, we present an observational determination of the c-Mvir (or delta_c-Mvir) relation in the mass range of 10^14< Mvir <10^16 (solar mass) using a sample of 63 X-ray luminous clusters. The best-fit power law relation, which is roughly independent of the values of Omega_M and Lambda, is c propto Mvir^(-0.5) or delta_c propto Mvir^(-1.2), indicating n=-0.7 for a scale-free power spectrum of the primordial density fluctuations. We discuss the possible reasons for the conflict with the predictions by typical CDM models such as SCDM, LCDM and OCDM.
%U http://arxiv.org/abs/astro-ph/9911347v1