A Survey of Disc Thickness and Viscosity in Circumbinary Accretion: Binary Evolution, Variability, and Disc Morphology

Abstract

Much of the parameter space relevant to the evolution of astrophysical circumbinary accretion discs remains unexplored. We have carried out a suite of circumbinary disc simulations surveying both disc thickness and kinematic viscosity, using both constant-$\nu$ and constant-$\alpha$ prescriptions. We focus primarily on disc aspect ratios between $0.1$ and $0.033$, and on viscosities between $\nu =0.0005$ and $\nu =0.008$ (in units of binary semi-major axis and orbital frequency), and specialise to circular equal-mass binaries. Both factors strongly influence the evolution of the binary semi-major axis: at $\nu =0.0005,$ inspirals occur at aspect ratios $\lesssim 0.059$, while at $\nu =0.004$ inspirals occur only at aspect ratios $\lesssim 0.04$. Inspirals occur largely because of the increasingly strong negative torque on the binary by streams of material which lag the binary, with negligible contributions from resonant torques excited in the circumbinary disc. We find that reductions in accretion rate occur when simulations are initialised too far from the eventual quasi-steady state driven by interaction with the binary, rather than being intrinsically linked to the disc aspect ratio. We find not only that the cavity size increases as viscosity is decreased, but that thinner circumbinary discs become more eccentric. Our results suggest that supermassive black hole binaries should be driven, more rapidly than previous estimates, from $\sim$parsec separations to distances where gravitational waves drive their inspiral, potentially reducing the number of binaries observable by pulsar timing arrays.

20 pages, 21 figures, published in MNRAS

References in corpus (26)

• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• The Population of Viscosity- and Gravitational Wave-Driven Supermassive Black Hole Binaries Among Luminous AGN
• Viscous Hydrodynamics Simulations of Circumbinary Accretion Discs: Variability, Quasi-Steady State, and Angular Momentum Transfer
• Hydrodynamic Torques in Circumbinary Accretion Disks
• Circumbinary Accretion from Finite and Infinite Disks
• Orbital Evolution of Equal-mass Eccentric Binaries due to a Gas Disk: Eccentric Inspirals and Circular Outspirals
• Characteristic Signatures in the Thermal Emission from Accreting Binary Black Holes
• Three Dimensional MHD Simulation of Circumbinary Accretion Disks -2. Net Accretion Rate
• Equilibrium eccentricity of accreting binaries
• Tidal Torques on Misaligned Disks in Binary Systems
• The evolution of large cavities and disc eccentricity in circumbinary discs
• The dynamics of eccentric accretion discs in superhump systems
• Star Formation in Accretion Disks and SMBH Growth
• Quasi-Periodicity of Supermassive Binary Black Hole Accretion Approaching Merger
• Gap, shadows, spirals, streamers: SPHERE observations of binary-disk interactions in GG Tau A
• Mass-ratio and Magnetic Flux-Dependence of Modulated Accretion from Circumbinary Disks
• Candidate Periodically Variable Quasars from the Dark Energy Survey and the Sloan Digital Sky Survey
• Mini-disk accretion onto spinning black hole binaries: quasi-periodicities and outflows
• Electromagnetic Signatures from Supermassive Binary Black Holes Approaching Merger
• Preventing Anomalous Torques in Circumbinary Accretion Simulations
• DISCO: A 3D Moving-Mesh Magnetohydrodynamics Code Designed for the Study of Astrophysical Disks
• On the planetary interpretation of multiple gaps and rings in protoplanetary disks seen by ALMA
• Long-Lived Eccentric Modes in Circumbinary Disks
• Discovery of a Candidate Binary Supermassive Black Hole in a Periodic Quasar from Circumbinary Accretion Variability
• Resolved Multifrequency Radio Observations of GG Tau
• How bright are the gaps in circumbinary disk systems?

Cited by in corpus (38)

• Electromagnetic Counterparts to Massive Black Hole Mergers
• Black Hole Binary Formation in AGN Discs: From Isolation to Merger
• Contracting and Expanding Binary Black Holes in 3D Low-Mass AGN Disks: The Importance of Separation
• Long-term Evolution of Binary Orbits Induced by Circumbinary Disks
• The Decoupling of Binaries from Their Circumbinary Disks
• Wide twin binaries are extremely eccentric: evidence of twin binary formation in circumbinary disks
• A unified accretion disc model for supermassive black holes in galaxy formation simulations: method and implementation
• Evolution and final fate of massive post-common-envelope binaries
• Population III star formation in an X-ray background: III. Periodic radiative feedback and luminosity induced by elliptical orbits
• How cooling influences circumbinary discs
• Eccentric Binaries in Retrograde Disks
• On the Role of Gas Cooling in the Dynamics of Circumbinary Disks
• Measuring eccentricity and gas-induced perturbation from gravitational waves of LISA massive black hole binaries
• Modelling the accretion and feedback of supermassive black hole binaries in gas-rich galaxy mergers
• From spherical stars to disk-like structures: 3D common-envelope evolution of massive binaries beyond inspiral
• Disk induced binary precession: Implications for dynamics and multi-messenger observations of black hole binaries
• RABBITS -- I. The crucial role of nuclear star formation in driving the coalescence of supermassive black hole binaries
• Probing the eccentricity in protostellar discs -- Modeling kinematics and morphologies
• Viscous circumbinary protoplanetary discs -- I. Structure of the inner cavity
• Systematics in tests of general relativity using LISA massive black hole binaries
• Suppressed accretion onto massive black hole binaries surrounded by thin disks
• Accretion onto a binary from a polar circumbinary disc
• Dynamics and spin alignment in massive, gravito-turbulent circumbinary discs around supermassive black hole binaries
• Orbital dynamics in the GG Tau A system: investigating its enigmatic disc
• Changing-Look Inspirals: Trends and Switches in AGN Disk Emission as Signposts for Merging Black Hole Binaries
• BH-BH mergers with & without EM counterpart: A model for stable tertiary mass transfer in hierarchical triple systems
• Migration of Accreting Planets and Black Holes in Disks
• Impact of a binary black hole on its outer circumbinary disc
• Radiation Magnetohydrodynamic Simulation of sub-Eddington Circumbinary Disk around an Equal-mass Massive Black Hole Binary
• Hot, cold, and multi-component accretion flows around supermassive black hole binaries
• Tracking on-the-fly massive black hole binary evolution and coalescence in galaxy simulations: RAMCOAL
• On Variation of Light Curves and Broad Emission Lines for Periodic QSOs from co-rotating Supermassive binary black holes in elliptical orbits
• Analytical and Numerical Analysis of Circumbinary Disk Dynamics -- I: Coplanar Systems
• The imprint of gas on gravitational waves from LISA intermediate-mass black hole binaries
• Insights from Analytical Theory of Eccentric Circumbinary Disks
• Viscous circumbinary protoplanetary discs -- II. Disc effects on the binary orbit
• Eccentric Disks from Gaseous Rings around Equal-Mass, Circular Binaries
• Luminous Fast Blue Optical Transients and Type Ibn/Icn SNe from Wolf-Rayet/Black Hole Mergers