Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks
The spin–orbit misalignment of stellar-mass black hole (sBH) binaries provides important constraints on the formation channels of merging sBHs. Here, we study the role of secular spin–orbit resonance in the evolution of an sBH binary component around a supermassive BH (SMBH) in an AGN disk. We consi...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acccf1 |
| _version_ | 1797700002879897600 |
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| author | Gongjie Li Hareesh Gautham Bhaskar Bence Kocsis Douglas N. C. Lin |
| author_facet | Gongjie Li Hareesh Gautham Bhaskar Bence Kocsis Douglas N. C. Lin |
| author_sort | Gongjie Li |
| collection | DOAJ |
| description | The spin–orbit misalignment of stellar-mass black hole (sBH) binaries provides important constraints on the formation channels of merging sBHs. Here, we study the role of secular spin–orbit resonance in the evolution of an sBH binary component around a supermassive BH (SMBH) in an AGN disk. We consider the sBH’s spin precession due to the J _2 moment introduced by a circum-sBH disk within the warping/breaking radius of the disk. We find that the sBH’s spin–orbit misalignment (obliquity) can be excited via spin–orbit resonance between the sBH binary’s orbital nodal precession and the sBH spin precession driven by a massive circum-sBH disk. Using an α -disk model with Bondi–Hoyle–Lyttleton accretion, the resonances typically occur for sBH binaries with semimajor axis of 1 au and at a distance of ∼1000 au around a 10 ^7 M _⊙ SMBH. The spin–orbit resonances can lead to high sBH obliquities and a broad distribution of sBH binary spin–spin misalignments. However, we note that the Bondi–Hoyle–Lyttleton accretion is much higher than that of Eddington accretion, which typically results in spin precession being too low to trigger spin–orbit resonances. Thus, secular spin–orbit resonances can be quite rare for sBHs in AGN disks. |
| first_indexed | 2024-03-12T04:15:56Z |
| format | Article |
| id | doaj.art-43e3026c226843d698b20d49ed92dc42 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:15:56Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-43e3026c226843d698b20d49ed92dc422023-09-03T10:36:11ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195014810.3847/1538-4357/acccf1Secular Spin–Orbit Resonances of Black Hole Binaries in AGN DisksGongjie Li0https://orcid.org/0000-0001-8308-0808Hareesh Gautham Bhaskar1https://orcid.org/0000-0002-5181-0463Bence Kocsis2https://orcid.org/0000-0002-4865-7517Douglas N. C. Lin3https://orcid.org/0000-0001-5466-4628Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology , Atlanta, GA 30332, USA ; gongjie.li@physics.gatech.eduCenter for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology , Atlanta, GA 30332, USA ; gongjie.li@physics.gatech.eduRudolf Peierls Centre for Theoretical Physics, University of Oxford , Parks Road, Oxford, OX1 3PU, UKDepartment of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95064, USAThe spin–orbit misalignment of stellar-mass black hole (sBH) binaries provides important constraints on the formation channels of merging sBHs. Here, we study the role of secular spin–orbit resonance in the evolution of an sBH binary component around a supermassive BH (SMBH) in an AGN disk. We consider the sBH’s spin precession due to the J _2 moment introduced by a circum-sBH disk within the warping/breaking radius of the disk. We find that the sBH’s spin–orbit misalignment (obliquity) can be excited via spin–orbit resonance between the sBH binary’s orbital nodal precession and the sBH spin precession driven by a massive circum-sBH disk. Using an α -disk model with Bondi–Hoyle–Lyttleton accretion, the resonances typically occur for sBH binaries with semimajor axis of 1 au and at a distance of ∼1000 au around a 10 ^7 M _⊙ SMBH. The spin–orbit resonances can lead to high sBH obliquities and a broad distribution of sBH binary spin–spin misalignments. However, we note that the Bondi–Hoyle–Lyttleton accretion is much higher than that of Eddington accretion, which typically results in spin precession being too low to trigger spin–orbit resonances. Thus, secular spin–orbit resonances can be quite rare for sBHs in AGN disks.https://doi.org/10.3847/1538-4357/acccf1Black hole spin-flipDynamical evolutionGravitational wave sourcesOrbits |
| spellingShingle | Gongjie Li Hareesh Gautham Bhaskar Bence Kocsis Douglas N. C. Lin Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks The Astrophysical Journal Black hole spin-flip Dynamical evolution Gravitational wave sources Orbits |
| title | Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks |
| title_full | Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks |
| title_fullStr | Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks |
| title_full_unstemmed | Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks |
| title_short | Secular Spin–Orbit Resonances of Black Hole Binaries in AGN Disks |
| title_sort | secular spin orbit resonances of black hole binaries in agn disks |
| topic | Black hole spin-flip Dynamical evolution Gravitational wave sources Orbits |
| url | https://doi.org/10.3847/1538-4357/acccf1 |
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