THREE-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATIONS OF CIRCUMBINARY ACCRETION DISKS: DISK STRUCTURES AND ANGULAR MOMENTUM TRANSPORT

By Ji-Ming Shi, Julian Krolik, S. Lubow, J. Hawley. 2011

181 citations recorded by the source corpus.

We present the first three-dimensional magnetohydrodynamic (MHD) simulations of a circumbinary disk surrounding an equal-mass binary. The binary maintains a fixed circular orbit of separation a. As in previous hydrodynamic simulations, strong torques by the binary can maintain a gap of radius ≃ 2a. Streams curve inward from r ≃ 2a toward the binary; some of their mass passes through the inner boundary, while the remainder swings back out to the disk. However, we also find that near its inner edge the disk develops both a strong m = 1 asymmetry and growing orbital eccentricity. Because the MHD stresses introduce more matter into the gap, the total torque per unit disk mass is ≃ 14 times larger than found previously. The inner boundary accretion rate per unit disk mass is ≃ 40 times greater than found from previous hydrodynamic calculations. The implied binary shrinkage rate is determined by a balance between the rate at which the binary gains angular momentum by accretion and loses it by gravitational torque. The large accretion rate brings these two rates nearly into balance, but in net, we find that , and its magnitude is about 2.7 times larger than predicted by the earlier hydrodynamic simulations. If the binary comprises two massive black holes, the accretion rate may be great enough for one or both to be an active galactic nucleus, with consequences for the physical state of the gas both in the disk body and in its inner gap.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/331efccbfef1272f58fb4ed40fde5ca225bd220e

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In Astronomy and Astrophysics

1. Zoltán Haiman
2. E. Barausse
3. M. Volonteri
4. A. Sesana
5. A. MacFadyen
6. D. D’Orazio
7. C. Caprini
8. Emanuele Berti

In Instrumentation

1. E. Barausse
2. M. Volonteri
3. A. Sesana
4. F. Haardt
5. J. Regan
6. Zoltán Haiman
7. Nicola Tamanini
8. C. Caprini

Citations in the corpus

• Evolution of binary black holes in self gravitating discs. Dissecting the torques (2012, background): “…discs, exploiting a variety of analytical and numerical techniques (Ivanov et al. 1999; Armitage & Natarajan 2002, 2005; Hayasaki et al. 2007, 2008; MacFadyen & Milosavljević 2008; Hayasaki 2009; Cuadra et al. 2009; Lodato et al. 2009; Nixon et al. 2011; Roedig et al. 2011; Shi et al. 2011).”
• BINARY BLACK HOLE ACCRETION FROM A CIRCUMBINARY DISK: GAS DYNAMICS INSIDE THE CENTRAL CAVITY (2013, methodology): “…simulations have been performed in 2D (MacFadyen & Milosavljević 2008) (hereafter MM08), (Cuadra et al. 2009; D’Orazio et al. 2012) and in 3D (Hayasaki et al. 2007; Farris et al. 2011, 2012; Noble et al. 2012; Shi et al. 2012; Roedig et al. 2012; Bode et al. 2012; Giacomazzo et al. 2012).”
• Unveiling the gravitational universe at μ-Hz frequencies (2019, background): “Because of copious shock-heating, gas near the MBHs is expected to be unusually hot [47, 50, 239].”
• Accretion into the central cavity of a circumbinary disc (2012, methodology): “Similar overdense lumps have also been found and described in the 3D MHD simulations of Shi et al. (2012); more recently, Roedig et al. (2011, 2012) have also mentioned the contributions of such lumps to fluctuations in the accretion rate.”