Institution(s): 1. University of Geneva
In addition to the use of clusters as cosmic telescopes, the HFF initiative gives us an unprecedented view of the matter distribution in clusters themselves. This precise mass reconstruction allows us to study in exquisite detail the dynamics of the HFF clusters, which gives us insight on the processes governing the formation of cosmic structures, on the large-scale matter distribution, and on the properties of dark matter. In this respect, X-ray observations with XMM-Newton and Chandra provide extremely useful complementary information which helps us disentangling the merger history of these systems and tell us about the baryonic physics. In this talk, I will give an overview of the joint X-ray effort on the HFF clusters and present some of the first results.