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 ^ { -1 } as a result of the anisotropic 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 \sim 10 ^ { 7 } M _ { \odot } BH the ejected disk has a characteristic size of tens of thousands of Schwarzschild radii and an accretion lifetime of \sim 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 .