Hydrodynamic accretion onto black holes

We consider adiabatic accretion onto a black hole in the hydrodynamic approximation with zero viscosity. For a slowly rotating black hole, the desired solution is a perturbation of a spherically symmetric flow. We obtain an analytic solution for such a perturbation, and find the correction to the accretion rate and the shape of the sonic surface. We take a similar approach to the accretion of matter onto a slowly moving black hole. Our fundamental result is that neither black hole rotation nor slow motion alters the essential nature of accretion. As before, this result can be extended to supersonic velocities in a collisionless flow, with the shape of the sonic surface and the accretion rate remaining virtually unchanged.