2021ApJ...906...34K

We present a generally applicable formalism for modeling the emission, absorption, reflection, and reprocessing of radiation by moving plasma streams close to a Kerr black hole. The formalism can be used to investigate the observational signatures of a wide range of phenomena, including (i) the reflection of coronal X-ray radiation off plasma plunging from the inner edge of a black hole accretion disk toward the black hole, (ii) the reflection of coronal X-ray emission off the upper layers of a geometrically thick accretion flow, (iii) the illumination of the accretion disk by a corona moving with relativistic velocities toward or away from the accretion disk, and (iv) the emission from a jet forming close to the black hole. After introducing the general relativistic treatment, we show the results for a fast wind forming close to a Kerr black hole. The approach presented here can be used to model X-ray spectral, timing, reverberation, and polarization data.