Implications for Gravitational Waves

Rates depend on number density of IMBH, types of interactions, formation process.

If $M_{\rm init}\ifmmode {\mathbin{\lower 3pt\hbox {$\,\rlap{\raise 8pt\hbox{$\char... ...{$\rlap{\raise 8pt\hbox{$\char'076$}}\mathchar''7218\,$}}} $}\fi 10^2\,M_\odot$ (Pop III, young clusters):

Poor LIGO/VIRGO sources (freq too low).

In clusters, IMBH could be LISA sources.

If $M_{\rm init}\sim 10-50\,M_\odot$ (old clusters):

$\sim$Tens of LIGO-II detections per year.

LISA rate also increases.

In either case, $e$ is high for LISA because of three-body interactions (K. Gültekin).

Precession, orbital decay observable.

IMBH into SMBH would be perfect high mass ratio source.