BINARY BLACK HOLE ACCRETION FROM A CIRCUMBINARY DISK: GAS DYNAMICS INSIDE THE CENTRAL CAVITY

By B. Farris, P. Duffell, A. MacFadyen, Zoltán Haiman. 2013

185 citations recorded by the source corpus.

We present the results of two-dimensional (2D) hydrodynamical simulations of circumbinary disk accretion using the finite-volume code DISCO. This code solves the 2D viscous Navier–Stokes equations on a high-resolution moving mesh which shears with the fluid flow, greatly reducing advection errors in comparison with a fixed grid. We perform a series of simulations for binary mass ratios in the range 0.026 ⩽ q ⩽ 1.0, each lasting longer than a viscous time so that we reach a quasi-steady accretion state. In each case, we find that gas is efficiently stripped from the inner edge of the circumbinary disk and enters the cavity along accretion streams, which feed persistent “mini disks” surrounding each black hole. We find that for q ≳ 0.1, the binary excites eccentricity in the inner region of the circumbinary disk, creating an overdense lump which gives rise to enhanced periodicity in the accretion rate. The dependence of the periodicity on mass ratio may provide a method for observationally inferring mass ratios from measurements of the accretion rate. We also find that for all mass ratios studied, the magnitude of the accretion onto the secondary is sufficient to drive the binary toward larger mass ratio. This suggests a mechanism for biasing mass-ratio distributions toward equal mass.

Subfields: Astronomy and Astrophysics, Biomedical Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/5c79a817fc8ee5dedd4d10f5d9eacb8a336b53af

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Citations in the corpus

A Population of Short-Period Variable Quasars from PTF as Supermassive Black Hole Binary Candidates (2016, background): “Hydrodynamical simulations of SMBHBs with higher mass ratios (q > 0.3) predict the existence of several periodic components in the variability (Roedig et al. 2012; Shi et al. 2012; D’Orazio, Haiman & MacFadyen 2013; Farris et al. 2014).”
Assisted inspirals of stellar mass black holes embedded in AGN discs: solving the ‘final au problem’ (2016, methodology): “…of a near-equal-mass binary with a circumbinary disk has been addressed by many hydrodynamical simulations, beginning with Artymowicz & Lubow (1994) (see, e.g. Hayasaki, Mineshige & Sudou 2007; Cuadra et al. 2009; Roedig et al. 2011; Shi et al. 2012; Farris et al. 2014 for more recent examples).”
A systematic search for close supermassive black hole binaries in the Catalina Real-time Transient Survey (2015, background): “Farris et al. (2014) describe how periodic mass accretion rates in a SMBH binary system can give rise to an overdense lump in the inner circumbinary accretion disk (CAD) and that the observation of periodicity in quasar emission would be associated with this.”