Black holes and neutron stars are believed to be the compact remnants of formerly massive stars that passed through their evolution and ejected their outer envelopes in supernova explosions (some black holes, such as those thought to exist in the cores of some galaxies, may have other origins). These compact stellar objects are characterized by strong magnetic and gravitational fields. Many are accreting matter from nearby companions, giving rise to the emission of short wavelength radiation. The Principal Investigator proposes to study the radiation emitted by black holes and neutron stars and the distortion of this radiation by strong magnetic and gravitational fields.