---
_id: '17613'
abstract:
- lang: eng
  text: We study the interaction of a supermassive black hole (SMBH) binary and a
    standard radiatively efficient thin accretion disk. We examine steady-state configurations
    of the disk and migrating SMBH system, self-consistently accounting for tidal
    and viscous torques and heating, radiative diffusion limited cooling, gas and
    radiation pressure, and the decay of the binary's orbit. We obtain a "phase diagram"
    of the system as a function of binary parameters, showing regimes in which both
    the disk structure and migration have a different character. Although massive
    binaries can create a central gap in the disk at large radii, the tidal barrier
    of the secondary causes a significant pile-up of gas outside of its orbit, which
    can lead to the closing of the gap. We find that this spillover occurs at an orbital
    separation as large as ~200 M_7^{-1/2} gravitational radii, where M = 10^7 M_7
    Msun is the total binary mass. If the secondary is less massive than ~10^6 Msun,
    then the gap is closed before gravitational waves (GWs) start dominating the orbital
    decay. In this regime, the disk is still strongly perturbed, but the piled-up
    gas continuously overflows as in a porous dam, and crosses inside the secondary's
    orbit. The corresponding migration rate, which we label Type 1.5, is slower than
    the usual limiting cases known as Type I and II migration. Compared to an unperturbed
    disk, the steady-state disk in the overflowing regime is up to several hundred
    times brighter in the optical bands. Surveys such as PanSTARRS or LSST may discover
    the periodic variability of this population of binaries. Our results imply that
    the circumbinary disks around SMBHs can extend to small radii during the last
    stages of their merger, when they are detectable by LISA, and may produce coincident
    electromagnetic (EM) emission similar to active galactic nuclei (AGN).
alternative_title:
- 'Overflow and migration: SMBH binaries'
article_processing_charge: No
article_type: original
author:
- 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
- first_name: Abraham
  full_name: Loeb, Abraham
  last_name: Loeb
citation:
  ama: 'Kocsis B, Haiman Z, Loeb A. Gas pile-up, gap overflow and Type 1.5 migration
    in circumbinary discs: Application to supermassive black hole binaries. <i>Monthly
    Notices of the Royal Astronomical Society</i>. 2012;427(3):2680-2700. doi:<a href="https://doi.org/10.1111/j.1365-2966.2012.22118.x">10.1111/j.1365-2966.2012.22118.x</a>'
  apa: 'Kocsis, B., Haiman, Z., &#38; Loeb, A. (2012). Gas pile-up, gap overflow and
    Type 1.5 migration in circumbinary discs: Application to supermassive black hole
    binaries. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University
    Press. <a href="https://doi.org/10.1111/j.1365-2966.2012.22118.x">https://doi.org/10.1111/j.1365-2966.2012.22118.x</a>'
  chicago: 'Kocsis, Bence, Zoltán Haiman, and Abraham Loeb. “Gas Pile-up, Gap Overflow
    and Type 1.5 Migration in Circumbinary Discs: Application to Supermassive Black
    Hole Binaries.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford
    University Press, 2012. <a href="https://doi.org/10.1111/j.1365-2966.2012.22118.x">https://doi.org/10.1111/j.1365-2966.2012.22118.x</a>.'
  ieee: 'B. Kocsis, Z. Haiman, and A. Loeb, “Gas pile-up, gap overflow and Type 1.5
    migration in circumbinary discs: Application to supermassive black hole binaries,”
    <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 427, no. 3. Oxford
    University Press, pp. 2680–2700, 2012.'
  ista: 'Kocsis B, Haiman Z, Loeb A. 2012. Gas pile-up, gap overflow and Type 1.5
    migration in circumbinary discs: Application to supermassive black hole binaries.
    Monthly Notices of the Royal Astronomical Society. 427(3), 2680–2700.'
  mla: 'Kocsis, Bence, et al. “Gas Pile-up, Gap Overflow and Type 1.5 Migration in
    Circumbinary Discs: Application to Supermassive Black Hole Binaries.” <i>Monthly
    Notices of the Royal Astronomical Society</i>, vol. 427, no. 3, Oxford University
    Press, 2012, pp. 2680–700, doi:<a href="https://doi.org/10.1111/j.1365-2966.2012.22118.x">10.1111/j.1365-2966.2012.22118.x</a>.'
  short: B. Kocsis, Z. Haiman, A. Loeb, Monthly Notices of the Royal Astronomical
    Society 427 (2012) 2680–2700.
date_created: 2024-09-05T13:28:17Z
date_published: 2012-12-11T00:00:00Z
date_updated: 2024-09-24T07:40:02Z
day: '11'
doi: 10.1111/j.1365-2966.2012.22118.x
extern: '1'
intvolume: '       427'
issue: '3'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1111/j.1365-2966.2012.22118.x
month: '12'
oa: 1
oa_version: Published Version
page: 2680-2700
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  issn:
  - 0035-8711
  - 1365-2966
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Gas pile-up, gap overflow and Type 1.5 migration in circumbinary discs: Application
  to supermassive black hole binaries'
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 427
year: '2012'
...