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Title: FAST COALESCENCE OF MASSIVE BLACK HOLE BINARIES FROM MERGERS OF GALACTIC NUCLEI: IMPLICATIONS FOR LOW-FREQUENCY GRAVITATIONAL-WAVE ASTROPHYSICS

Journal Article · · Astrophysical Journal Letters
; ; ;  [1]
  1. Astronomisches Rechen-Institut, Zentrum fuer Astronomie, University of Heidelberg, D-69120 Heidelberg (Germany)

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 equal-mass massive black hole binaries (MBHBs) 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 Laser Interferometer Space Antenna (LISA). Based on our results for equal-mass mergers, and given that the hardening rate of unequal-mass binaries is similar, we expect that LISA will see between {approx}10 and {approx} few x 10{sup 2} such events every year, depending on the particular massive black hole (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 {approx}> 0.001-0.01.

OSTI ID:
21562694
Journal Information:
Astrophysical Journal Letters, Vol. 732, Issue 2; Other Information: DOI: 10.1088/2041-8205/732/2/L26; ISSN 2041-8205
Country of Publication:
United States
Language:
English