Hydrodynamic Torques in Circumbinary Accretion Disks

Moody, Mackenzie; Shi, Ji-Ming; Stone, James M.

doi:10.3847/1538-4357/ab09ee

Cited by 152 publications

(160 citation statements)

References 30 publications

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“…However, several recent simulations of circumbinary disks have found that, contrary to previous results in the literature, accretion can also widen binaries within circumbinary disks, when the advective torque dominates over the gravitational torque (Miranda et al 2017;Muñoz et al 2019;Moody et al 2019). Whether gravitational or advective torques dominate depends on details such as the sink prescription used for accretion (Tang et al 2017).…”

Section: Origin Of Twin Binariesmentioning

confidence: 90%

Discovery of an equal-mass ‘twin’ binary population reaching 1000 + au separations

El-Badry

Rix

Tian

et al. 2019

Monthly Notices of the Royal Astronomical Society

122

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We use a homogeneous catalog of 42,000 main-sequence wide binaries identified by Gaia to measure the mass ratio distribution, p(q), of binaries with primary masses 0.1 < M 1 /M < 2.5, mass ratios 0.1 q < 1, and separations 50 < s/AU < 50, 000. A well-understood selection function allows us to constrain p(q) in 35 independent bins of primary mass and separation, with hundreds to thousands of binaries in each bin. Our investigation reveals a sharp excess of equal-mass "twin" binaries that is statistically significant out to separations of 1,000 to 10,000 AU, depending on primary mass. The excess is narrow: a steep increase in p(q) at 0.95 q < 1, with no significant excess at q 0.95. A range of tests confirm the signal is real, not a data artifact or selection effect. Combining the Gaia constraints with those from close binaries, we show that the twin excess decreases with increasing separation, but its width (q 0.95) is constant over 0.01 < a/AU < 10, 000. The wide twin population would be difficult to explain if the components of all wide binaries formed via core fragmentation, which is not expected to produce strongly correlated component masses. We conjecture that wide twins formed at closer separations (a 100 AU), likely via accretion from circumbinary disks, and were subsequently widened by dynamical interactions in their birth environments. The separation-dependence of the twin excess then constrains the efficiency of dynamical widening and disruption of binaries in young clusters. We also constrain p(q) across 0.1 q < 1. Besides changes in the twin fraction, p(q) is independent of separation at fixed primary mass over 100 s/AU < 50, 000. It is flatter than expected for random pairings from the IMF but more bottom-heavy for wide binaries than for binaries with a 100 AU.

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Section: Origin Of Twin Binariesmentioning

confidence: 90%

Discovery of an equal-mass ‘twin’ binary population reaching 1000 + au separations

El-Badry

Rix

Tian

et al. 2019

Monthly Notices of the Royal Astronomical Society

122

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“…Muñoz et al (2019) found a positive torque with a similar setup, resulting in widening, rather than shrinking of the SMBHB orbit. Recent work by Moody et al (2019) has also found positive torques, even with an apparently slower sink prescription.…”

Section: Open Questions Related To Theory Of Smbhbs With Sub-mentioning

confidence: 92%

“…As a result, the total luminosity of the binary can significantly exceed, even by 1-2 orders of magnitude, that of a Shakura-Sunyaev disk with the same mass and external large-scale accretion rate (see also Lodato et al 2009;Kocsis et al 2012b,a). Interestingly, the additional power must come at the expense of the binary's binding energy, and is therefore directly tied to disk's contribution to the binary's inspiral rate (although this extra energy source does not exist if the disk torques are positive and cause an outspiral, rather than an inspiral; see Tang et al 2017;Muñoz et al 2019;Moody et al 2019). Also interestingly, this point was noted in the context of pre-main sequence stellar binaries by Terquem and Papaloizou (2017).…”

Section: Theory and Simulationsmentioning

confidence: 97%

“…However, recent work (Tang et al, 2017;Muñoz et al, 2019;Moody et al, 2019) has called this conclusion into question, because in the quasi-steady state and the much higher spatial resolutions reached in these works, the torques appear dominated by gas very close to the individual BHs, and cause outward, rather than inward-migration (see discussion presented below in this section Open Questions related to theory of SMB-HBs with subparsec separations.…”

Section: Interactions With Gasmentioning

confidence: 99%

See 1 more Smart Citation

The quest for dual and binary supermassive black holes: A multi-messenger view

Rosa

Vignali

Bogdanović

et al. 2019

New Astronomy Reviews

180

123

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The quest for binary and dual supermassive black holes (SMBHs) at the dawn of the multi-messenger era is compelling. Detecting dual active galactic nuclei (AGN)-active SMBHs at projected separations larger than several parsecs-and binary AGN-probing the scale where SMBHs are bound in a Keplerian binary-is an observational challenge. The study of AGN pairs (either dual or binary) also represents an overarching theoretical problem in cosmology and astrophysics. The AGN triggering calls for detailed knowledge of the hydrodynamical conditions of gas in the imminent surroundings of the SMBHs and, at the same time, their duality calls for detailed knowledge on how galaxies assemble through major and minor mergers and grow fed by matter along the filaments of the cosmic web. This review describes the techniques used across the electromagnetic spectrum to detect dual and binary AGN candidates and proposes new avenues for their search. The current observational status is compared with the state-of-the-art numerical simulations and models for formation of dual and binary AGN. Binary SMBHs are among the loudest sources of gravitational waves (GWs) in the Universe. The search for a background of GWs at nHz frequencies from inspiralling SMBHs at low redshifts, and the direct detection of signals from their coalescence by the Laser Interferometer Space Antenna in the next decade, make this a theme of major interest for multi-messenger astrophysics. This review discusses the future facilities and observational strategies that are likely to significantly advance this fascinating field.

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“…Here fEM parameterizes the unknown duty cycle of CO binaries below a maximum orbital period that have at least one bright component (bolometric luminosity at the Eddington luminosity or greater), and χ is the fraction of CO binaries at of order 100 ks orbital periods that will merge rather than stall. For example, χ could be less than one if gas dynamics slow or prevent merger (Tang et al 2017;Derdzinski et al 2019;Muñoz et al 2019;Moody et al 2019), or if the binary is broken up during dynamical formation (as happens for the 2-body and 3-body mergers of, e.g., Rodriguez et al 2018a).…”

Section: Discussionmentioning

confidence: 99%

Detecting gravitational self-lensing from stellar-mass binaries composed of black holes or neutron stars

D’Orazio

Stefano

2019

Monthly Notices of the Royal Astronomical Society

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We explore a unique electromagnetic signature of stellar-mass compact-object binaries long before they are detectable in gravitational waves. We show that gravitational lensing of light emitting components of a compact-object binary, by the other binary component, could be detectable in the nearby universe. This periodic lensing signature could be detected from present and future X-ray observations, identifying the progenitors of binaries that merge in the LIGO band, and also unveiling populations that do not merge, thus providing a tracer of the compact-object binary population in an enigmatic portion of its life. We argue that periodically repeating lensing flares could be observed for ∼ < 100 ks orbital-period binaries with the future Lynx X-ray mission, possibly concurrent with gravitational wave emission in the LISA band. Binaries with longer orbital periods could be more common and be detectable via single lensing flares, though with reliance on a model for the flare, testable by observations of future flares. Non-detection of such events, even with existing X-ray observations, will help to constrain the population of EM bright compact-object binaries.

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Hydrodynamic Torques in Circumbinary Accretion Disks

Cited by 152 publications

References 30 publications

Discovery of an equal-mass ‘twin’ binary population reaching 1000 + au separations

Discovery of an equal-mass ‘twin’ binary population reaching 1000 + au separations

The quest for dual and binary supermassive black holes: A multi-messenger view

Detecting gravitational self-lensing from stellar-mass binaries composed of black holes or neutron stars

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