Universal AdS Black Holes in Theories with 16 Supercharges and Their Microstates.

We provide a universal microscopic counting for the microstates of the asymptotically AdS black holes and black strings that arise as solutions of the half-maximal gauged supergravity in 4 and 5 dimensions. These solutions can be embedded in all M-theory and type II string backgrounds with an AdS vacuum and 16 supercharges and provide an infinite set of examples dual to N=2 and N=4 conformal field theories in four and three dimensions, respectively. The counting is universal and it is performed by either studying the large N limit of the relevant supersymmetric index of the dual field theory or by using the charged Cardy formula.