X-rays from the inner accretion flow

Giovanni Miniutti, Laboratoire APC

Active black holes dissipate the large majority of the accretion energy in the innermost regions of the accretion flow. Most of the energy release is in the form of X-rays which carry information about the physical state and dynamics of the emitting gas, potentially enabling us to probe the nature of the spacetime in the General Relativistic regime close to the event horizon. I will review some of the recent progress in the field, focussing on X-ray observations of both AGN and Galactic black holes in which spectral and variability data strongly indicate that the detailed study of relativistic effects within a few Scwarzschild radii from the black hole is well within the grasp of current X-ray observatories. The future prospects of this active research field will also be discussed.