BOUNDS FOR MASS AND ROTATION OF BLACK-HOLES IN THE OBSERVABLE UNIVERSE

The bounds for the energy change rate of a Maxwell field in the outer space of a rotating black hole, calculated by de Vries (1994) and de V ries (1995), enable us to deduce limits for the rotation and the mass of black holes. For this purpose we assume that a certain part of the anisotropies of the cosmic background radiation is due to absorption o r superradiance of black holes (Teukolsky, 1973, Starobinskii and Chur ilov, 1973). The knowledge of these anisotropies yields bounds for rot ation and mass of the black holes in the observable universe.