Class <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="script">S</mml:mi></mml:math> Superconformal Indices from Maximal Supergravity

We present a new gauging of maximal supergravity in five spacetime dimensions with gauge group containing ISO(5), involving the local scaling symmetry of the metric, and admitting a supersymmetric anti-de Sitter vacuum. We show this maximal supergravity to arise by consistent truncation of M theory on the (nonspherical, nonparallelizable) six-dimensional geometry associated to a stack of N M5 branes wrapped on a smooth Riemann surface. The existence of this truncation allows us to holographically determine the complete, universal spectrum of light operators of the dual four-dimensional N=2 theory of class S. We then compute holographically the superconformal index of the dual field theory at large N, finding perfect agreement with previously known field theory results in specific limits.