X-ray diagnostics of black hole spin

Christopher Reynolds, University of Maryland

The spin of a black hole has a strong influence on the inner regions of its accretion disk, affecting the mass-energy conversion efficiency, as well as the characteristic disk temperatures, temporal frequencies and gravitational redshifts. Given a sufficient understanding of these influences, we can constrain the black hole spin by studying the spectral and timing properties of X-ray emissions from the inner accretion disk. After reviewing our current theoretical understanding and uncertainties, I will summarize the current observational results on the spins of both stellar-mass and supermassive black holes. I will end by discussing the promise of future high-throughput X-ray observatories.