Journal article
Eccentric black hole mergers in active galactic nuclei
- Abstract:
- The astrophysical origin of gravitational wave transients is a timely open question in the wake of discoveries by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo. In active galactic nuclei (AGNs), binaries form and evolve efficiently by interaction with a dense population of stars and the gaseous AGN disk. Previous studies have shown that stellar-mass black hole (BH) mergers in such environments can explain the merger rate and the number of suspected hierarchical mergers observed by LIGO/Virgo. The binary eccentricity distribution can provide further information to distinguish between astrophysical models. Here we derive the eccentricity distribution of BH mergers in AGN disks. We find that eccentricity is mainly due to binary–single (BS) interactions, which lead to most BH mergers in AGN disks having a significant eccentricity at 0.01 Hz, detectable by the Laser Interferometer Space Antenna. If BS interactions occur in isotropic-3D directions, then 8%–30% of the mergers in AGN disks will have eccentricities at 10 Hz above e10 Hz ≳ 0.03, detectable by LIGO/Virgo/Kamioka Gravitational Wave Detector, while 5%–17% of mergers have e10 Hz ≥ 0.3. On the other hand, if BS interactions are confined to the AGN–disk plane due to torques from the disk, with 1–20 intermediate binary states during each interaction, or if BHs can migrate to ≲ 10−3 pc from the central supermassive BH, then 10%–70% of the mergers will be highly eccentric (e10 Hz ≥ 0.3), consistent with the possible high eccentricity in GW190521.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, 687.6KB, Terms of use)
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- Publisher copy:
- 10.3847/2041-8213/abd4d3
Authors
- Publisher:
- IOP Publishing
- Journal:
- Astrophysical Journal Letters More from this journal
- Volume:
- 907
- Issue:
- 1
- Article number:
- L20
- Publication date:
- 2021-01-21
- Acceptance date:
- 2020-12-17
- DOI:
- EISSN:
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2041-8213
- ISSN:
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2041-8205
- Language:
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English
- Keywords:
- Pubs id:
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1140268
- Local pid:
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pubs:1140268
- Deposit date:
-
2021-11-24
Terms of use
- Copyright holder:
- Tagawa et al.
- Copyright date:
- 2021
- Rights statement:
- ©2021. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
- Licence:
- CC Attribution (CC BY)
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