---
_id: '17557'
abstract:
- lang: eng
  text: The black hole (BH) binaries in active galactic nuclei (AGN) are expected
    to form mainly through scattering encounters in the ambient gaseous medium. Recent
    simulations, including our own, have confirmed this formation pathway is highly
    efficient. We perform 3D smoothed particle hydrodynamics (SPH) simulations of
    BH scattering encounters in AGN discs. Using a range of impact parameters, we
    probe the necessary conditions for binary capture and how different orbital trajectories
    affect the dissipative effects from the gas. We identify a single range of impact
    parameters, typically of width ∼0.86−1.59 binary Hill radii depending on AGN disc
    density, that reliably leads to binary formation. The periapsis of the first encounter
    is the primary variable that determines the outcome of the initial scattering.
    We find an associated power law between the energy dissipated and the periapsis
    depth to be ΔE ∝ r−b with b = 0.42 ± 0.16, where deeper encounters dissipate more
    energy. Excluding accretion physics does not significantly alter these results.
    We identify the region of parameter space in initial energy versus impact parameter
    where a scattering leads to binary formation. Based on our findings, we provide
    a ready-to-use analytic criterion that utilizes these two pre-encounter parameters
    to determine the outcome of an encounter, with a reliability rate of >90
    per cent. As the criterion is based directly on our simulations, it provides a
    reliable and highly physically motivated criterion for predicting binary scattering
    outcomes which can be used in population studies of BH binaries and mergers around
    AGN.
article_processing_charge: No
article_type: original
author:
- first_name: Connar
  full_name: Rowan, Connar
  last_name: Rowan
- first_name: Henry
  full_name: Whitehead, Henry
  last_name: Whitehead
- first_name: Tjarda
  full_name: Boekholt, Tjarda
  last_name: Boekholt
- first_name: Bence
  full_name: Kocsis, Bence
  last_name: Kocsis
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
citation:
  ama: Rowan C, Whitehead H, Boekholt T, Kocsis B, Haiman Z. Black hole binaries in
    AGN accretion discs – II. Gas effects on black hole satellite scatterings. <i>Monthly
    Notices of the Royal Astronomical Society</i>. 2023;527(4):10448-10468. doi:<a
    href="https://doi.org/10.1093/mnras/stad3641">10.1093/mnras/stad3641</a>
  apa: Rowan, C., Whitehead, H., Boekholt, T., Kocsis, B., &#38; Haiman, Z. (2023).
    Black hole binaries in AGN accretion discs – II. Gas effects on black hole satellite
    scatterings. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford
    University Press (OUP). <a href="https://doi.org/10.1093/mnras/stad3641">https://doi.org/10.1093/mnras/stad3641</a>
  chicago: Rowan, Connar, Henry Whitehead, Tjarda Boekholt, Bence Kocsis, and Zoltán
    Haiman. “Black Hole Binaries in AGN Accretion Discs – II. Gas Effects on Black
    Hole Satellite Scatterings.” <i>Monthly Notices of the Royal Astronomical Society</i>.
    Oxford University Press (OUP), 2023. <a href="https://doi.org/10.1093/mnras/stad3641">https://doi.org/10.1093/mnras/stad3641</a>.
  ieee: C. Rowan, H. Whitehead, T. Boekholt, B. Kocsis, and Z. Haiman, “Black hole
    binaries in AGN accretion discs – II. Gas effects on black hole satellite scatterings,”
    <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 527, no. 4. Oxford
    University Press (OUP), pp. 10448–10468, 2023.
  ista: Rowan C, Whitehead H, Boekholt T, Kocsis B, Haiman Z. 2023. Black hole binaries
    in AGN accretion discs – II. Gas effects on black hole satellite scatterings.
    Monthly Notices of the Royal Astronomical Society. 527(4), 10448–10468.
  mla: Rowan, Connar, et al. “Black Hole Binaries in AGN Accretion Discs – II. Gas
    Effects on Black Hole Satellite Scatterings.” <i>Monthly Notices of the Royal
    Astronomical Society</i>, vol. 527, no. 4, Oxford University Press (OUP), 2023,
    pp. 10448–68, doi:<a href="https://doi.org/10.1093/mnras/stad3641">10.1093/mnras/stad3641</a>.
  short: C. Rowan, H. Whitehead, T. Boekholt, B. Kocsis, Z. Haiman, Monthly Notices
    of the Royal Astronomical Society 527 (2023) 10448–10468.
date_created: 2024-09-05T10:32:08Z
date_published: 2023-01-01T00:00:00Z
date_updated: 2024-09-18T12:11:28Z
doi: 10.1093/mnras/stad3641
extern: '1'
intvolume: '       527'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1093/mnras/stad3641
month: '01'
oa: 1
oa_version: Published Version
page: 10448-10468
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  issn:
  - 0035-8711
  - 1365-2966
publication_status: published
publisher: Oxford University Press (OUP)
quality_controlled: '1'
scopus_import: '1'
status: public
title: Black hole binaries in AGN accretion discs – II. Gas effects on black hole
  satellite scatterings
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 527
year: '2023'
...