Multi--dimensional IWP Solutions for Heterotic String Theory
  We present extremal stationary solutions that generalize the Israel-Wilson-Perjes class for the d+3-dimensional low-energy limit of heterotic string theory with n >= d+1 U(1) gauge fields compactified on a d-torus. A rotating axisymmetric dyonic solution is obtained using the matrix Ernst potential formulation and expressed in terms of a single d+1 X d+1-matrix harmonic function. By studying the asymptotic behaviour of the field configurations we define the physical charges of the field system. The extremality condition makes the charges to saturate the Bogomol'nyi-Prasad-Sommerfield (BPS) bound. The gyromagnetic ratios of the corresponding field configurations appear to have arbitrary values. A subclass of rotating dyonic black hole-type solutions arises when the NUT charges are set to zero. In the particular case d=1, n=6, which correspond to N=4, D=4 supergravity, the found dyon reproduces the supersymmetric dyonic solution constructed by Bergshoeff et al. 
Alfredo Herrera-Aguilar and Oleg Kechkin