Evaporation of 2-Dimensional Black Holes

We present a detailed analysis of results from a new study of t he quantum evaporation of Callan-GiddingsHarvey-Strominger (CGHS) black holes within the mean-field approximation. This semi-classical theory incorporates back reaction. Our analytical and numerical cal cul tions show that, while some of the assumptions underlying the standard evaporation paradigm are borne out , several are not. One of the anticipated properties we confirm is that the semi-classical space-time is asymptot ically flat at right future null infinity,I R , yet incomplete in the sense that null observers reach a future Cauchy h orizon in finite affine time. Unexpected behavior includes that the Bondi mass traditionally used in the liter ature can become negative even when the area of the horizon is macroscopic; an improved Bondi mass remains posi tive until the end of semi-classical evaporation, yet the final value can be arbitrarily large relative to the Pl anck mass; and the flux of the quantum radiation at