Anti-de Sitter black holes in gauged N=8 supergravity

We present new anti-de Sitter black hole solutions of gauged N = 8, SO(8) supergravity, which is the massless sector of the AdS(4) x S-7 vacuum Of M-theory, By focusing on the U(1)(4) Cartan subgroup, we find non-extremal 1, 2, 3 and 4 charge solutions, In the extremal limit, they may preserve up to 1/2, 1/4, 1/8 and 1/8 of the supersymmetry, respectively. In the limit of vanishing SO(8) coupling constant, the solutions reduce to the familiar black holes of the Mg X T-7 vacuum, but have very different interpretation since there are no winding states on S-7 and no U-duality. In contrast to the T7 compactification, moreover, we find no static multi-center solutions. Also in contrast, the S7 fields appear "already dualized" so that the 4 charges may be all electric or all magnetic rather than 2 electric and 2 magnetic. Curiously, however, the magnetic solutions preserve no supersymmetries. We conjecture that a subset of the extreme electric black holes preserving 1/2 the supersymmetry may be identified with the S7 Kaluza-Klein spectrum, with the non-abelian SO(8) quantum numbers provided by the fermionic zero-modes. (C) 1999 Elsevier Science B.V. All rights reserved.