Constraining Recoiling Velocities of Black Holes Ejected by
  Gravitational Radiation in Galaxy Mergers
  Recent general relativistic simulations have shown that the coalescence of
two spinning black holes (BH) can lead to recoiling speeds of the BH remnant of
up to thousands of km/s as a result of the gravitational radiation emission. It
is important that the accretion disc remains bound to ejected BH within the
region where the gas orbital velocity is larger than the ejection speed. We
considered the situation when the recoiling kick radius coincides with the
radius of the broad line region (BLR). We show that in this situation the
observed polarization data of accretion disk emission allow to determine the
value of the recoil velocity. We present the estimates of the kick velocity for
AGN with determined polarization data.
