Tachyon back-reaction on d=2 string black hole

We describe a static solution for d=2 critical string theory including the tachyon T but with its potential V(T) set to zero. This solution thus incorporates a tachyon back-reaction and, when T=0, reduces to the black hole solution. When T≠0 we find that: (1) The Schwarzschild horizon of the above black hole splits into two, resembling Reissner-Nordstrom horizons, and (2) the curvature scalar develops new singularities at the horizons. We show that these features will persist even when V(T) is nonzero. We present a time-dependent extension of our static solution and discuss some possible methods for removing the above singularities. (orig.)