Probing Intermediate Mass Black Holes in M87 through Multi-Wavelength
  Gravitational Wave Observations
  We analyze triple systems composed of the super massive black hole (SMBH)
near the center of M87 and a pair of black holes (BHs) with masses in the range
$10-10^3$ $M_{\odot}$. We consider the post Newtonian precession as well as the
Kozai-Lidov interactions at the quadruple and octupole levels in modeling the
evolution of binary black hole (BBH) under the influence of the SMBH.
Kozai-Lidov oscillations enhance the gravitational wave (GW) signal in some
portions of the parameter space. We identify frequency peaks and examine the
detectability of GWs with LISA as well as future observatories such as
$\mu$Ares and DECIGO. We show examples in which GW signal can be observed with
a few or all of these detectors. Multi-Wavelength GW spectroscopy holds the
potential to discover stellar to intermediate mass BHs near the center of M87.
We estimate the rate, $\Gamma$, of collisions between the BBHs and flyby stars
at the center of M87. Our calculation suggests $\Gamma < 10$ $\rm{Gyr}^{-1}$
for a wide range of the mass and semi-major axes of the inner binary.
