## [1102.4855] Fast coalescence of massive black hole binaries from mergers of galactic nuclei: implications for low-frequency gravitational-wave astrophysics

Authors: Miguel Preto, Ingo Berentzen, Peter Berczik, Rainer Spurzem

Date: 23 Feb 2011

Abstract: We investigate a purely stellar dynamical solution to the Final Parsec Problem. Galactic nuclei resulting from major mergers are not spherical, but show some degree of triaxiality. With $N$-body simulations, we show that massive black hole binaries (MBHB) hosted by them will continuously interact with stars on centrophilic orbits and will thus inspiral — in much less than a Hubble time — down to separations at which gravitational wave (GW) emission is strong enough to drive them to coalescence. Such coalescences will be important sources of GWs for future space-borne detectors such as the {\it Laser Interferometer Space Antenna} (LISA). Based on our results, we expect that LISA will see between $\sim 10$ to $\sim {\rm few} \times 10ˆ2$ such events every year, depending on the particular MBH seed model as obtained in recent studies of merger trees of galaxy and MBH co-evolution. Orbital eccentricities in the LISA band will be clearly distinguishable from zero with $e \gtrsim 0.001-0.01$.

#### Feb 28, 2011

1102.4855 (/preprints)
2011-02-28, 23:28