  Study of astrophysics of black holes and neutron stars has taken a new turn
in the present decade with the realization that sub-Keplerian flows and the
associated centrifugal barrier near the horizon or the surface of a neutron
star play a major role in deciding the nature of the emitted spectra and the
formation of outflows from the accreting matter. This region may remain steady
or oscillate depending on the accretion rate, specific angular momentum and
specific energy of the flow. Intricacies of oscillation may depend on the
degree of feedback the inflow receives from the outflow. This region may emit
hard or soft X-rays depending on relative numbers of hot elections and soft
photons intercepted by this region. We discuss how these properties come about
and how they explain the observational results of black hole candidates.
