CLUMP-3D: Testing ΛCDM with Galaxy Cluster Shapes

The $\Lambda$CDM model of structure formation makes strong predictions on concentration and shape of DM (dark matter) halos, which are determined by mass accretion processes. Comparison between predicted shapes to observations provide a geometric test of the $\Lambda$CDM model. A full three-dimensional analysis of the cluster mass distribution can provide accurate and precise measurements. We accomplish this with a multi-probe 3D analysis of the X-ray regular CLASH (Cluster Lensing And Supernova survey with Hubble) clusters combining strong and weak lensing, X-ray photometry and spectroscopy and the Sunyaev-Zel'dovich effect. The cluster shapes and concentrations are consistent with $\Lambda$CDM predictions. The CLASH clusters are randomly oriented, as expected given the sample selection criteria. Shapes agree with numerical results for DM-only halos, which hints at baryonic physics being not so effective in making halos rounder.