Time dependent black holes and scalar hair
  We show how to correctly account for scalar accretion onto black holes in
scalar field models of dark energy by a consistent expansion in terms of a slow
roll parameter. We find an exact solution for the scalar field within our
Hubble volume which is regular on both black hole and cosmological event
horizons, and compute the back reaction of the scalar on the black hole,
calculating the resulting expansion of the black hole. Our results are
independent of the relative size of black hole and cosmological event horizons.
We comment on the implications for more general black hole accretion, and the
no hair theorems.
