Relativistic Accretion Disk Structure Revisited

Riffert, H.; Herold, H.

doi:10.1086/176161

Cited by 182 publications

(169 citation statements)

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“…Using nothing more than the Kerr metric, basic conservation laws of mass, momentum, angular momentum and energy, and assumptions of axisymmetry and steady state, the NT model (see also Page & Thorne 1974;Riffert & Herold 1995) derives an analytical formula for the differential luminosity dL(R)/dR emitted by the disk as a function of radius R.…”

Section: Accretion Disk Theorymentioning

confidence: 99%

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

2013

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The spins of ten stellar black holes have been measured using the continuumfitting method. These black holes are located in two distinct classes of X-ray binary systems, one that is persistently X-ray bright and another that is transient. Both the persistent and transient black holes remain for long periods in a state where their spectra are dominated by a thermal accretion disk component. The spin of a black hole of known mass and distance can be measured by fitting this thermal continuum spectrum to the thin-disk model of Novikov and Thorne; the key fit parameter is the radius of the inner edge of the black hole's accretion disk. Strong observational and theoretical evidence links the inner-disk radius to the radius of the innermost stable circular orbit, which is trivially related to the dimensionless spin parameter a * of the black hole (|a * | < 1). The ten spins that have so far been measured by this continuum-fitting method range widely from a * ≈ 0 to a * > 0.95. The robustness of the method is demonstrated by the dozens or hundreds of independent and consistent measurements of spin that have been obtained for several black holes, and through careful consideration of many sources of systematic error. Among the results discussed is a dichotomy between the transient and persistent black holes; the latter have higher spins and larger masses. Also discussed is recently discovered evidence in the transient sources for a correlation between the power of ballistic jets and black hole spin.

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Section: Accretion Disk Theorymentioning

confidence: 99%

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

2013

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“…The θ component of momentum balance equation (3) can be integrated assuming hydrostatic equilibrium around the equatorial plane (i.e. θ ≈ π/2) to obtain local disc half-height expression (Riffert & Herold 1995;Peitz & Appl 1997),…”

Section: Accretion Equations Of Motionmentioning

confidence: 99%

Estimation of bipolar jets from accretion discs around Kerr black holes

Kumar

Chattopadhyay

2017

Monthly Notices of the Royal Astronomical Society

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We analyse flows around a rotating black hole and obtain self-consistent accretionejection solutions in full general relativistic prescription. Entire energy-angular momentum parameter space is investigated in the advective regime to obtain shocked and shock-free accretion solutions. Jet equations of motion are solved along the von-Zeipel surfaces computed from the post-shock disc, simultaneously with the equations of accretion disc along the equatorial plane. For a given spin parameter, the mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock location. Interestingly, we obtain all types of possible jet solutions, for example, steady shock solution with multiple critical points, bound solution with two critical points and smooth solution with single critical point. Multiple critical points may exist in jet solution for spin parameter a s 0.5. The jet terminal speed generally increases if the accretion shock forms closer to the horizon and is higher for corotating black hole than the counter-rotating and the non-rotating one. Quantitatively speaking, shocks in jet may form for spin parameter a s > 0.6 and jet shocks range between 6r g and 130r g above the equatorial plane, while the jet terminal speed v j∞ > 0.35c if Bernoulli parameter E 1.01 for a s > 0.99.

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“…The relativistic correction factors for a thin accretion disc around a Kerr BH have been given by [15], …”

Section: G ∼mentioning

confidence: 99%

“…The equation of the conservation of mass remains valid, while hydrostatic equilibrium in the vertical direction leads to a corrected expression for the half thickness of the disc [15,16]:…”

Section: G ∼mentioning

confidence: 99%

A toy model for magnetized neutrino-dominated accretion flows

Lei

Wang

Zhang

et al. 2010

Sci. China Phys. Mech. Astron.

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In this paper, we present a simplified model for magnetized neutrino-dominated accretion flow (NDAF) in which effect of black hole (BH) spin is taken into account by adopting a set of relativistic correction factor, and the magnetic field is parameterized as β , the ratio of the magnetic pressure to the total pressure. It is found that the disc properties are sensitive to the values of the BH spin and β , and more energy can be extracted from NDAF for the faster spin and lower β .black hole, gamma-ray bursts, accretion disc, magnetic fieldThe nature of the central engine of gamma-ray bursts (GRBs) remains unclear, and the favoured models invoke binary merger or collapse of compact objects. These models lead to the formation of a transient hot and dense accretion torus/disc around a black hole (BH) of a few solar masses. If an accretion disc is cooled mainly via the neutrino loss, it is referred to as neutrino-dominated accretion flow (NDAF) [1].NDAF has been extensively discussed by many authors [2][3][4][5]. However, the effects of the magnetic fields are usually neglected in NDAF due to the intrinsic complexity.Magnetic fields could play an important role in the central engine in some aspects [10], e.g., a bold gamma-ray polarization [6], a higher magnetic energy density required by the reverse shock [7,8], and the energy argument for X-ray flares [9]. These considerations stimulate us to discuss a model of magnetized NDAF.Recently, Chen & Beloborodov [4], Gu et al.[5] and Shibata et al. [11] argued that the general relativistic (GR) effects are important for NDAF, and we introduce GR correction factors in our model. This paper is organized as follows. In Sect. 1 we describe the magnetized NDAF in the frame of a relativistic thin disc of steady state, and the effects of MHD stress are described. The main equations are based on refs.[2] and [3], but corrected with GR factors. We solve the set of equations for the solutions of NDAF in Sect. 2, and compute disc temperature, density and neutrino luminosities. The effects of the free parameters are also discussed. Finally, we summarize our results and discuss some related issues in Sect. 3. Magnetized Neutrino-Dominated Accretion FlowsAs is well known, the magneto-rotational instability (MRI) plays an important role in angular momentum transportation of accretion disc [11,12]. Currently, it is widely believed that the viscosity in accretion flows is effectively determined by the turbulent motion of fluid, being related to the magnetic stress. Therefore, we consider only the magnetic viscosity in this model.The magnetic viscous shear r t ϕ can be expressed as where B ϕ is given byThe parameter β is the ratio of the magnetic pressure to the total pressure. A roughly steady state is reached when the growing rate of B ϕ generated by differential rotation of the radial field is equal to its loss rate due to buoyancy effect, and B ϕ can be estimated as [13]

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Relativistic Accretion Disk Structure Revisited

Cited by 182 publications

References 0 publications

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

Estimation of bipolar jets from accretion discs around Kerr black holes

A toy model for magnetized neutrino-dominated accretion flows

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