ACT and XXL galaxy cluster survey: first results, expectations and cosmological implication., Jean-Baptiste Juin (DAA-PUC)

Since 2007 the Atacama Cosmology Telescope observed 1000 sdeg of the southern sky and produced the first blind Sunyaev-Zel'dovich galaxy cluster catalog. From space, the XMM-LSS survey will be extended (the XXL project) to cover 50 sdeg, producing a large sample of new galaxy clusters. In this talk I will review the first results of ACT and the expectations for XXL, showing the complementarity of both observations. Indeed, this multi-wavelength approach is essential to understand the galaxy clusters gas physics and, will allow new and independant - from CMB, BAO, SN-Ia - constraints on cosmological parameters and more specifically the dark-energy equation of state.