Accretion onto a moving black hole: An exact solution

We present an analytic solution for the steady-state, subsonic accretion of a gaseous medium onto a Schwarzschild or Kerr black hole. The black hole moves at a constant velocity through the medium, which is uniform and at rest far from the hole and obeys a P=ρ adiabatic equation of state. In the case of a rotating Kerr black hole, the flow is fully three dimensional, but the accretion rate does not depend on the orientation of the hole’s spin with respect to the incident direction of the flow.