We describe astrophysical processes around a black hole keeping primarily the physics of
accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of …

We describe new optically thin solutions for rotating accretion flows around black holes and
neutron stars. These solutions are advection dominated, so that most of the viscously …

Black hole X-ray binaries (BHXBs) are known to display five distinct spectral states. In order
of increasing luminosity these are the quiescent state, low state, intermediate state, high …

Approximate formulae for the instantaneous scattered radiation spectra are derived in the
Thomson and Klein-Nishina regimes, assuming that the relativistic electrons are described …

We study the spectral properties of a very general class of accretion disks which can be
decomposed into three distinct components apart from a shock at $ r= r_s $:(1) An optically …

We show that most of hot, optically thin accretion disk models which ignore advective
cooling are not self-consistent. We have found new types of optically thin disk solutions …

We present models of the soft X-ray transients, A0620-00, V404 Cyg, and X-ray Nova Mus
1991, in quiescence. In each source, we postulate that there is an outer region, extending …

We provide a unified description of thermal equilibria of black hole accretion disks, including
the newly-discovered advection-dominated solutions. We classify the solutions on the basis …

Simplified assumptions about the thermodynamics of the electrons are normally employed in
general-relativistic magnetohydrodynamic (GRMHD) simulations of accretion on to black …

It has been found that a class of optically-thin two-temperature advection-dominated
accretion solutions explains many observations of low-luminosity accreting black holes …