Stationary axion/dilaton solutions and supersymmetry Original Research Article

We present a new set of supersymmetric stationary solutions of pure N = 4, d = 4 supergravity (and, hence, of low-energy effective string theory) that generalize (and include) the Israel-Wilson-Perjés solutions of Einstein-Maxwell theory. All solutions have 14 of the supersymmetries unbroken and some have 12. The full solution is determined by two arbitrary complex harmonic functions 1,2 which transform as a doublet under SL(2), R) S duality and N complex constants k(n) that transform as an SO(N) vector. This set of solutions is, then, manifestly duality invariant. When the harmonic functions are chosen to have only one pole, all the general resulting point-like objects have supersymmetric rotating asymptotically Taub-NUT metrics with 12 or 14 of the supersymmetries unbroken. The static, asymptotically flat metrics describe supersymmetric extreme black holes. Only those breaking 34 of the supersymmetries have regular horizons. The stationary asymptotically flat metrics do not describe black holes when the angular momentum does not vanish, even in the case in which 34 of the supersymmetries are broken.