Hypervelocity binaries from close encounters with a SMBH-IMBH binary:
  orbital properties and diagnostics
  Hypervelocity binaries (HVBs) can be produced by a close encounter between
stellar binaries and supermassive black hole (SMBH)-intermediate massive black
hole (IMBH) binaries. We perform scattering experiments between tight stellar
binaries and an SMBH-IMBH binary (within the observationally allowed
parameters), using high-precision N-body integrations. Simulation results show
that only a few HVBs can be produced in the Galactic center if it harbors a
$4\times10^3M_\odot$ IMBH. However, we find that tight HVBs can be efficiently
produced in prograde coplanar orbits with respect to the SMBH-IMBH binary.
Therefore, the trajectories of the HVBs provide a promising way to constrain
the IMBH orbital plane, if one exists. More importantly, we find that the
ejected tight binaries are eccentric. For other galaxies hosting equal-mass
SMBH binaries for which the HVB ejection rate is much higher relative to
SMBH-IMBH binaries, these ejected compact binaries constitute promising
extragalactic merger sources that could be detected by gravitational wave
detectors.
