Black Holes in Binary Systems: Instability of Disk Accretion

Lightman, Alan P.; Eardley, Douglas M.

doi:10.1086/181377

Cited by 604 publications

(499 citation statements)

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“…Naively, we expect equilibrium curves with negative slopes in this diagram to be viscously unstable, as the vertically integrated stress W Rφ is proportional to the dissipation rate per unit area Q + which in turn is proportional to the accretion rateṀ , because, after all, it is the inflow of matter which is the source of accretion power. The negative sloped curve portions in the right of this diagram near Eddington accretion rates are radiation dominated, geometrically thin disks, and are viscously unstable by this criterion (Lightman & Eardley 1974). They are also thermally unstable (Shibazaki & Hōshi 1975;Shakura & Sunyaev 1976), as can be seen because Q + exceeds (is less than) Q − + Q adv above (below) these curve portions.…”

Section: Local Thermal Equilibria and Secular Instabilitiesmentioning

confidence: 85%

“…In geometrically thin accretion disks, where dynamical equilibrium on the inflow time requires the angular velocity and specific angular momentum of fluid orbits to be a function of radius and not of time, one can write down a time-dependent diffusion equation for the evolution of the surface mass density in the flow (Lynden-Bell & Pringle 1974;Lightman & Eardley 1974),…”

Section: Local Thermal Equilibria and Secular Instabilitiesmentioning

confidence: 99%

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General Overview of Black Hole Accretion Theory

Blaes

2013

Space Sci Rev

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I provide a broad overview of the basic theoretical paradigms of black hole accretion flows. Models that make contact with observations continue to be mostly based on the four decade old alpha stress prescription of Shakura & Sunyaev (1973), and I discuss the properties of both radiatively efficient and inefficient models, including their local properties, their expected stability to secular perturbations, and how they might be tied together in global flow geometries. The alpha stress is a prescription for turbulence, for which the only existing plausible candidate is that which develops from the magnetorotational instability (MRI). I therefore also review what is currently known about the local properties of such turbulence, and the physical issues that have been elucidated and that remain uncertain that are relevant for the various alpha-based black hole accretion flow models.

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Section: Local Thermal Equilibria and Secular Instabilitiesmentioning

confidence: 85%

Section: Local Thermal Equilibria and Secular Instabilitiesmentioning

confidence: 99%

General Overview of Black Hole Accretion Theory

Blaes

2013

Space Sci Rev

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“…1). The radiative transition would be continuous, were it not for the fact that the radiation pressure-dominated, radiative disk solution is thought to be unstable (Lightman & Eardley 1974). Assuming this instability manifests, then following the radiative transition, the disk immediately (on a thermal timescale) collapses to the corresponding gaspressure dominated solution satisfyingq − rad (T, θ) =q + visc (θ) for the same Σ, R d (see Shen & Matzner 2014, for a similar discussion in the context of tidal disruption events).…”

Section: Viscously-heated Radiatively Cooled Phasementioning

confidence: 99%

Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets

Margalit

Metzger

2016

Mon. Not. R. Astron. Soc.

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We show that the merger and tidal disruption of a C/O white dwarf (WD) by a neutron star (NS) binary companion provides a natural formation scenario for the PSR B1257+12 planetary system. Starting with initial conditions for the debris disk produced of the disrupted WD, we model its long term viscous evolution, including for the first time the effects of mass and angular momentum loss during the early radiatively inefficient accretion flow (RIAF) phase and accounting for the unusual C/O composition on the disk opacity. For plausible values of the disk viscosity α ∼ 10 −3 − 10 −2 and the RIAF mass loss efficiency, we find that the disk mass remaining near the planet formation radius at the time of solid condensation is sufficient to explain the pulsar planets. Rapid rocky planet formation via gravitational instability of the solid carbon-dominated disk is facilitated by the suppression of vertical shear instabilities due to the high solid-to-gas ratio. Additional evidence supporting a WD-NS merger scenario includes (1) the low observed occurrence rate of pulsar planets ( 1% of NS birth), comparable to the expected WD-NS merger rate; (2) accretion by the NS during the RIAF phase is sufficient to spin PSR B1257+12 up to its observed 6 ms period; (3) similar models of 'low angular momentum' disks, such as those produced from supernova fallback, find insufficient mass reaching the planet formation radius. The unusually high space velocity of PSR B1257+12 of 326 km s −1 suggests a possible connection to the Calcium-rich transients, dim supernovae which occur in the outskirts of their host galaxies and were proposed to result from mergers of WD-NS binaries receiving SN kicks. The C/O disk composition implied by our model likely results in carbon-rich planets with diamond interiors.

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“…A promising model for the ρ class variability is that it is driven by radiation pressure instability (Lightman & Eardley 1974;Taam & Lin 1984;Taam, Chen & Swank 1997). However, numerical simulations of the instability suggests that there is need to change the viscous prescription and take into account a fraction of energy dissipating in a corona to explain the overall X-ray modulation (e.g.…”

Section: Introductionmentioning

confidence: 99%

A model for the energy-dependent time-lag and rms of the heartbeat oscillations in GRS 1915+105

Mir

Misra

Pahari

et al. 2016

Mon. Not. R. Astron. Soc.

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Energy dependent phase lags reveal crucial information about the causal relation between various spectral components and about the nature of the accretion geometry around the compact objects. The time-lag and the fractional root mean square (rms) spectra of GRS 1915+105 in its heartbeat oscillation class/ρ state show peculiar behaviour at the fundamental and harmonic frequencies where the lags at the fundamental show a turn around at ∼ 10 keV while the lags at the harmonic do not show any turn around at least till ∼ 20 keV. The magnitude of lags are of the order of few seconds and hence cannot be attributed to the light travel time effects or Comptonization delays. The continuum X-ray spectra can roughly be described by a disk blackbody and a hard X-ray power-law component and from phase resolved spectroscopy it has been shown that the inner disk radius varies during the oscillation. Here, we propose that there is a delayed response of the inner disk radius (DROID) to the accretion rate such that r in (t) ∝ṁ β (t − τ d ). The fluctuating accretion rate drives the oscillations of the inner radius after a time delay τ d while the power-law component responds immediately. We show that in such a scenario a pure sinusoidal oscillation of the accretion rate can explain not only the shape and magnitude of energy dependent rms and time-lag spectra at the fundamental but also the next harmonic with just four free parameters.

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Black Holes in Binary Systems: Instability of Disk Accretion

Cited by 604 publications

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General Overview of Black Hole Accretion Theory

General Overview of Black Hole Accretion Theory

Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets

A model for the energy-dependent time-lag and rms of the heartbeat oscillations in GRS 1915+105

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Black Holes in Binary Systems: Instability of Disk Accretion

Cited by 604 publications

References 0 publications

General Overview of Black Hole Accretion Theory

General Overview of Black Hole Accretion Theory

Merger of a white dwarf–neutron star binary to 1029carat diamonds: origin of the pulsar planets

A model for the energy-dependent time-lag and rms of the heartbeat oscillations in GRS 1915+105

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Merger of a white dwarf–neutron star binary to 10²⁹carat diamonds: origin of the pulsar planets