O(6,22) BPS configurations of the heterotic string

We present a static multicenter magnetic solution of toroidally compactified heterotic string theory, which is T-duality covariant. The space-time geometry depends on the mass M and on the O(6,22) norm N of the magnetic charges. For a different range of parameters the (IM,N) solution includes (1) two-independent-positive-parameter extremal magnetic black holes with a nonsingular geometry in a stringy frame (a=1 black holes included), (2) a=root 3 extremal black holes, and (3) singular massive and massless magnetic white holes (repulsons). The electric multicenter solution is also given in an O(6,22)-symmetric form.