Mass distribution and Dynamical State of Galaxy Clusters in the LZLS Sample

Abstract

We use the weak gravitational lensing effect to study the mass distribution of a sample of 50 southern Abell clusters (0.05 z L X > 5 × 10 44 erg s -1 observed with ESO-VLT under uniform sky conditions and subarsecond (0.6 '' ) image quality. Their dynamical equibrium is assesed through comparison of the clusters mass estimates made by weak-lensing, velocity-dispersions and X-ray techniques. So far, for 24 clusters (Cypriano et al. 2004), we find: a) the center of their mass and light distributions are coincident for 77% of the sample; b) the elongations of the fitted mass profiles and of the light of the cD galaxies generally match with each other; c) although most of the clusters are found to be in dynamical equilibrium, those with T X ≥ 8 keV (or σ v ≥ 1120 km s -1 ) are the discordant ones. The preliminary bright arc statistics for our whole sample (LZLS) suggests the presence of a cut-off at z ~ 0.07 which is qualitatively consistent with predictions done in a ΛCDM cosmology (Meneghetti et al. 2003).