Class S 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 (non-spherical,
non-parallelisable) 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.