  Since black holes can only accrete sub-Keplerian matter, a companion black
hole orbiting on a circular and instantaneously Keplerian orbit around a
central, massive black hole in a galactic Centre will loss angular momentum and
energy to the accreting matter. This loss could be a significant fraction of
the loss due to gravitational wave (GW) emission. The corresponding GW signal
would be modified. We discuss this effects in the light of the modern accretion
disk theory.
