Modeling multipolar gravitational-wave emission from small mass-ratio mergers
by Barausse, Enrico and Buonanno, Alessandra and Hughes, Scott A. and Khanna, Gaurav and O’Sullivan, Stephen and Pan, Yi
19 pages, 14 figures, 6 tables
Using the effective-one-body (EOB) formalism and a time-domain Teukolsky code, we generate inspiral, merger, and ringdown waveforms in the small mass-ratio limit. We use EOB inspiral and plunge trajectories to build the Teukolsky equation source term, and compute full coalescence waveforms for a range of black hole spins. By comparing EOB waveforms that were recently developed for comparable mass binary black holes to these Teukolsky waveforms, we improve the EOB model for the (2,2), (2,1), (3,3), and (4,4) modes. Our results can be used to quickly and accurately extract useful information about merger waves for binaries with spin, and should be useful for improving analytic models of such binaries. Although in this analysis we only consider equatorial inspirals (orbital angular momentum parallel to spin), there is no issue of principle preventing us from considering inclined binaries. We will extend this analysis to examine misaligned spin-orbit configurations in future work.