  In this work we would like to address the issue of shock formation in black
hole accretion discs. We provide a {\it generalized two parameter solution
scheme} for multi-transonic, accretion and wind around Schwarzschild black
holes, by mainly concentrating on accretion solutions which may contain steady,
standing isothermal shocks. Such shocks conserve flow temperature by the
dissipation of energy at the shock location.Unlike previous works in this
field, our calculation is {\it not} restricted to any particular kind of
post-Newtonian gravitational potentials, rather we use {\it all} available
pseudo-Schwarzschild potentials to formulate and solve the equations governing
the accretion and wind only in terms of flow temperature $T$ and specific
angular momentum $\lambda$ of the flow. Our generalized formalism assures that
the shock formation is not just an artifact of a particular type of
gravitational potential, rather inclusion of all available black-hole
potentials demonstrates a substantially extended zone of parameter space
allowing for the possibility of shock formation. We thus arrive at the
conclusion that the standing shocks are essential ingredients in rotating,
advective accretion flows of isothermal fluid around a non-spinning
astrophysical black hole. Types of shocks discussed in this paper may appear to
be `bright' because of the huge amount of energy dissipation at shock, and the
quick removal of such energy to maintain the isothermality may power the strong
X-ray flares recently observed to be emerged from our Galactic centre.
  The results are discussed in connection to other astrophysical phenomena of
related interest, such as the QPO behaviour of galactic black hole candidates.
(Abridged).
