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Title: Binary-disk interaction. II. Gap-opening criteria for unequal-mass binaries

We study the interaction of an unequal-mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a supermassive black hole binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts on the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong nonaxisymmetric density perturbation that is produced in the disk, in response to the presence of the binary. Using smoothed particle hydrodynamics numerical simulations, we test two gap-opening criteria, one that assumes the geometry of the density perturbation is an ellipsoid/thick spiral and another that assumes a flat spiral geometry for the density perturbation. We find that the flat spiral gap-opening criterion successfully predicts which simulations will have a gap in the disk and which will not. We also study the limiting cases predicted by the gap-opening criteria. Since the viscosity in our simulations is considerably smaller than the expected value in the nuclear regionsmore » of gas-rich merging galaxies, we conclude that in such environments the formation of a circumbinary gap is unlikely.« less
Authors:
;  [1]
  1. Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)
Publication Date:
OSTI Identifier:
22348299
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; BINARY STARS; BLACK HOLES; COMPUTERIZED SIMULATION; DENSITY; DISTURBANCES; GALAXIES; GALAXY NUCLEI; GRAVITATIONAL INTERACTIONS; HYDRODYNAMICS; MASS; PERTURBATION THEORY; VISCOSITY