Multi-transonic Black Hole Accretion Discs with Dissipative Standing Shock


In this work we would like to address the issue of shock formation in black hole accretion discs. We provide a generalized two parameter solution scheme for inviscid, multi-transonic, isothermal accretion and wind around Schwarzschild black holes, by mainly concentrating on accretion solutions which may contain steady, standing dissipative shocks. By ‘dissipative’ shock, we mean a shock solution which conserves flow temperature in expense of energy dissipation at shock location. We use the vertically integrated 1.5 dimensional model to describe the disc structure where the equations of motion are written on the equatorial plane of the central accretor, assuming the flow to be in hydrostatic equilibrium in the transverse direction. Unlike previous works in this field, our calculation is not restricted to any particular kind of post-Newtonian gravitational potentials, rather we use 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 λ of the flow. Accretion flow is assumed to be non-dissipative everywhere, except possibly at the shock location, if any. We observe that a significant region of parameter space spanned by {λ, T} allows shock formation. 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 allows a substantially extended zone of parameter space allowing for the possibility of shock formation. We thus arrive at the conclusion that the dissipative standing shocks are essential ingredients in rotating advective accretion flows of isothermal fluid around a non-spinning astrophysical black hole. We clearly identify all possible shock solution which

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@inproceedings{Das2003MultitransonicBH, title={Multi-transonic Black Hole Accretion Discs with Dissipative Standing Shock}, author={Tapas Kumar Das and Jayant K. Pendharkar and Sanjit K. Mitra}, year={2003} }