Comments on the Newly Discovered Advection Dominated Flows Around Black holes and Neutron stars

Abstract

We provide complete and global solutions of transonic flows around black holes, in presence of advection, rotation, heating and cooling. We show that for any degree of advection, there may exist two critical viscosity parameters $α_{c1, c2}$ such that for $α<α_{c1}$ the flow may pass through the inner sonic point only. For $α_{c1} <α<α_{c2}$, the flow may have shock waves, and for $α>α_{c2}$, the flow may again pass through the inner sonic point, depending on flow parameters. No new topologies emerge other than what we found earlier while studying viscous isothermal transonic flows. These findings indicate that the newly discovered advection dominated flows do not constitute any new solutions.