The ultimate XMM extragalactic survey SQUARE_BRACKET_OPENaSQUARE_BRACKET_CLOSE

We propose a 1040ks/field XMM survey over 50 deg2, designed to constrain thedark energy equation of state using the 600 1,400 clusters of galaxies that wewill detect. The constraints that we will achieve on w_0 and w_a, of 0.7 and 2.4(10ks coverage) and 0.4 and 1.2 (40ks coverage) are at the level of the ultimateStageIV DETF accuracy estimates achievable by cluster studies. This survey willalso have lasting legacy value for cluster scaling laws and studies of AGN andXRB.