2 research outputs found
Hierarchical Black Hole Mergers in Active Galactic Nuclei
The origins of the stellar-mass black hole mergers discovered by LIGO/Virgo
are still unknown. Here we show that, if migration traps develop in the
\add{accretion} disks of Active Galactic Nuclei (AGNs) and promote the mergers
of their captive black holes, the majority of black holes within disks will
undergo hierarchical mergers---with one of the black holes being the remnant of
a previous merger. 40% of AGN-assisted mergers detected by LIGO/Virgo will
include a black hole with mass M, the mass limit from
stellar core collapse. Hierarchical mergers at traps in AGNs will exhibit black
hole spins (anti-)aligned with the binary's orbital axis, a distinct property
from other hierarchical channels. Our results are suggestive, although not
definitive (with Odds ratio of ), that LIGO's heaviest merger so far,
GW170729, could have originated from this channel.Comment: 6 pages, 3 figures; accepted in PR