  According to recent general-relativistic simulations, the coalescence of two
spinning black holes (BHs) could lead to recoil speeds of the BH remnant of up
to thousands of km/s as a result of the emission of gravitational radiation.
Such speeds would enable the merger product to escape its host galaxy. Here we
examine the circumstances resulting from a gas-rich galaxy merger under which
the ejected BH would carry an accretion disk with it and be observable. As the
initial BH binary emits gravitational radiation and its orbit tightens, a hole
is opened around it in the disk which delays the consumption of gas prior to
the eventual BH ejection. The punctured disk remains bound to the ejected BH
within the region where the gas orbital velocity is larger than the ejection
speed. For a ~10^7 solar mass BH the ejected disk has a characteristic size of
tens of thousands of Schwarzschild radii and an accretion lifetime of ~10^7
years. During that time, the ejected BH could traverse a considerable distance
and appear as an off-center quasar with a feedback trail along the path it left
behind. A small fraction of all quasars could be associated with an escaping
BH.
