Three-Dimensional Magnetohydrodynamic Simulations of Circumbinary Accretion Disks: Disk Structures and Angular Momentum Transport

Shi, Ji-Ming; Krolik, Julian H.; Lubow, Stephen H.; Hawley, John F.

doi:10.1088/0004-637x/749/2/118

Cited by 307 publications

(505 citation statements)

References 94 publications

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“…This precession is due to the highly non-Keplerian nature of the potential close to an unequal-mass eccentric binary such as HD 104237, and is a natural consequence of the fact that orbits in a non-Keplerian potential are not closed ellipses. To date, this effect has only been studied for discs around circular binaries in the context of supermassive black hole (SMBH) binaries (MacFadyen & Milosavljević 2008;Shi et al 2012;D'Orazio, Haiman, & MacFadyen 2013;Farris et al 2014). We find that the precession is uniform between 4 R 6 a b .…”

Section: Simulationsmentioning

confidence: 83%

Precession and accretion in circumbinary discs: the case of HD 104237

Dunhill

Cuadra

Dougados

2015

Monthly Notices of the Royal Astronomical Society

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We present the results of smoothed particle hydrodynamics (SPH) simulations of the disc around the young, eccentric stellar binary HD 104237. We find that the binary clears out a large cavity in the disc, driving a significant eccentricity at the cavity edge. This then precesses around the binary at a rate of˙ = 0.48 • T −1 b , which for HD 104237 corresponds to a precession period of 40 years. We find that the accretion pattern into the cavity and onto the binary changes with this precession, resulting in a periodic accretion variability driven purely by the physical parameters of the binary and its orbit. For each star we find that this results in order of magnitude changes in the accretion rate. We also find that the accretion variability allows the primary to accrete gas at a higher rate than the secondary for approximately half of each precession period. Using a large number of 3-body integrations of test particles orbiting different binaries, we find good agreement between the precession rate of a test particle and our SPH disc precession. These rates also agree very well with the precession rates predicted by the analytic theory of Leung & Lee (2013), showing that their prescription can be accurately used to predict long-term accretion variability timescales for eccentric binaries accreting from a disc. We discuss the implications of our result, and suggest that this process provides a viable way of preserving unequal mass ratios in accreting eccentric binaries in both the stellar and supermassive black hole regimes.

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Section: Simulationsmentioning

confidence: 83%

Precession and accretion in circumbinary discs: the case of HD 104237

Dunhill

Cuadra

Dougados

2015

Monthly Notices of the Royal Astronomical Society

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“…Numerical simulations have extensively shown that the SMBHB's orbital motion gives rise to enhanced periodicity in the mass accretion rates onto each black holes (e.g., Hayasaki et al 2008Hayasaki et al , 2013Shi et al 2012;Farris et al 2014 and references therein). This motivates systematic searches of SMBHB candidates through periodic optical variability (e.g., Graham et al 2015a;Liu et al 2015).…”

Section: Smbhb Modelmentioning

confidence: 99%

Spectroscopic Indication of a Centi-Parsec Supermassive Black Hole Binary in the Galactic Center of Ngc 5548

Wang

et al. 2016

ApJ

111

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As a natural consequence of cosmological hierarchical structure formation, sub-parsec supermassive black hole binaries (SMBHBs) should be common in galaxies but thus far have eluded spectroscopic identification. Based on four decades of optical spectroscopic monitoring, we report that the nucleus of NGC5548, a nearby Seyfert galaxy long suspected to have experienced a major merger about 1 billion yr ago, exhibits long-term variability with a period of ∼14 yr in the optical continuum and broad Hβ emission line. Remarkably, the double-peaked profile of Hβ shows systematic velocity changes with a similar period. These pieces of observations plausibly indicate that an SMBHB resides in the center of NGC5548. The complex, secular variations in the line profiles can be explained by orbital motion of a binary with equal mass and a semimajor axis of ∼22 light-days (corresponding to ∼18 milli-parsec). At a distance of 75Mpc, NGC5548 is one of the nearest sub-parsec SMBHB candidates that offers an ideal laboratory for gravitational wave detection.

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“…Binaries with 0.3 ∼ < q ∼ < 0.8 clear a lopsided central cavity in the disc, causing variability on three time-scales. The dominant period, (3 − 8)t bin is that of an over dense lump, orbiting at the ridge of the cavity, with additional periodicities at t bin and ≈ 0.5t bin (MacFadyen & Milosavljević 2008;Shi et al 2012;Noble et al 2012;Roedig et al 2012;D'Orazio et al 2013;Farris et al 2014). The dominant period depends on the size of the cavity, and thus on disc parameters, such as temperature and viscosity.…”

Section: Introductionmentioning

confidence: 99%

A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

D’Orazio

Haiman

Duffell

et al. 2015

Mon. Not. R. Astron. Soc.

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Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)t bin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3 − 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBsWith the corresponding 2−4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter t bin , among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K α line. The CBD model predicts additional periodic variability on time-scales of t bin and ≈ 0.5t bin , as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

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Three-Dimensional Magnetohydrodynamic Simulations of Circumbinary Accretion Disks: Disk Structures and Angular Momentum Transport

Cited by 307 publications

References 94 publications

Precession and accretion in circumbinary discs: the case of HD 104237

Precession and accretion in circumbinary discs: the case of HD 104237

Spectroscopic Indication of a Centi-Parsec Supermassive Black Hole Binary in the Galactic Center of Ngc 5548

A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

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