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Observational Signature of the `Boundary Layer' of Galactic and Extragalactic Black Holes

S. K. Chakrabarti·L. Titarchuk·D. Kazanas·K. Ebisawa
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Abstract

We present spectral properties of an accretion disk model, in which a Keplerian accretion disk is flanked by a sub-Keplerian halo component terminating at a standing shock. The post-shock region (which may be considered to be the boundary layer of a black hole) reprocesses the soft photons emitted from the Keplerian accretion disk. We show that switching of states (from hard to soft and vice versa) could be accomplished by a change in the accretion rate of the Keplerian disk component. Our consideration, for the first time, resolves a long-standing problem of identifying the illusive `Compton cloud' responsible for the switching of states.

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S. K. Chakrabarti, L. Titarchuk, D. Kazanas, K. Ebisawa. 1996-11-04. Observational Signature of the `Boundary Layer' of Galactic and Extragalactic Black Holes. https://arxiv.org/abs/astro-ph/9611018

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