On Some Transonic Aspects of General Relativistic Spherical Accretion   onto Schwarzschild Black Holes
  The equations governing general relativistic, spherically symmetric, hydrodynamic accretion of polytropic fluid onto black holes are solved in Schwarzschild metric to investigate some of the transonic properties of the flow. Only stationary solutions are discussed. For such accretion, it has been shown that real physical sonic points may form {\it even for flow with $\gamma < {4/3}$ or $\gamma > {5/3}$}. Behaviour of some flow variables in the close vicinity of the event horizon are studied as a function of specific energy and polytropic index of the flow. 
Tapas Kumar Das