http://arxiv.org/abs/1602.04226
We explore the evolution of stellar mass black hole binaries (BHBs) which are formed in self-gravitating AGN disks. Hardening due to three-body scattering and gaseous drag are effective mechanisms that reduce the semi-major axis of a BHB to radii where gravitational waves take over, on timescales shorter than the typical lifetime of the AGN disk. Taking observationally-motivated assumptions for the rate of star formation in AGN disks, we find a rate of disk-induced BHB mergers (R ~ 3/Gpc^3/yr, but with large uncertainties) that is competitive with existing estimates of the field rate of BHB mergers, and the approximate BHB merger rate implied by the recent Advanced LIGO detection of GW150914. BHBs formed thorough this channel will frequently be associated with current AGN, which are relatively rare within the sky error regions of future gravitational wave detector arrays. This channel could also possess a (potentially transient) electromagnetic counterpart due to super-Eddington accretion onto the stellar mass black hole following the merger.
N. Stone, B. Metzger and Z. Haiman
Tue, 16 Feb 16
34/71
Comments: 8 pages, 3 figures
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