Radiative Disk Winds from a Self-Similar Slim Disk

Watarai, Ken-ya; Fukue, Jun

doi:10.1093/pasj/51.5.725

Cited by 87 publications

(86 citation statements)

References 13 publications

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“…The self-similar solutions for the flux and effective temperature without magnetic field was firstly presented by Watarai & Fukue (1999). In comparison with their solutions (without magnetic field), in our solutions the flux and effective temperature depend on the toroidal component of magnetic field β1 explicitly (…”

Section: The Bolometric Luminositymentioning

confidence: 73%

The influence of large-scale magnetic field in the structure of supercritical accretion flow with outflow

Ghasemnezhad

Abbassi

2017

Monthly Notices of the Royal Astronomical Society

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We present the effects of ordered large scale magnetic field on the structure of supercritical accretion flow in the presence of outflow. In the cylindrical coordinates (r, ϕ, z), We write the 1.5 dimensional, the steady state ( ∂ ∂t = 0) and axisymmetric ( ∂ ∂ϕ = 0) inflow-outflow equations by using the self similar solutions. Also a model for radiation pressure supported accretion flow threaded by both toroidal and vertical components of magnetic field has been formulated. For studying the outflows, we adopt a radius dependent mass accretion rate aṡ M =Ṁ out ( . Also by following the previous works, we have considered the interchange of mass, radial and angular momentum and the energy between inflow and outflow. we have found numerically that two components of magnetic field have the opposite effects on the thickness of the disc and similar effects on the radial and angular velocities of the flow. We have found that the existence of the toroidal component of magnetic field will lead to increasing of radial and azimuthal velocities as well as the relative thickness of the disc, which is increased . Moreover, the thickness of the disc will decrease when the vertical component of magnetic field becomes important in magnetized flow. The solutions indicated that the mass inflow rate, the specific energy of outflow affect strongly on the advection parameter.We have shown that by increasing the two components of magnetic field, the temperature of the accretion flow will decrease significantly. On the other hand we have shown the bolometric luminosity of the slim discs for high values ofṁ(ṁ >> 1) is not sensitive to mass accretion rate and is kept constant (L ≈ 10L E ).

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Section: The Bolometric Luminositymentioning

confidence: 73%

The influence of large-scale magnetic field in the structure of supercritical accretion flow with outflow

Ghasemnezhad

Abbassi

2017

Monthly Notices of the Royal Astronomical Society

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“…The magnetospheric radius is obtained by the balance between the magnetic pressure of dipole fields and the radiation pressure of the disk for the case of the radiation dominated accretion disks. Applying self-similar solutions for slim disk (Watarai & Fukue 1999), the magnetospheric radius is obtained as r m /R * ≃ 1.7(α/0.1) 2/7 (Ṁ /10…”

Section: Conclusion and Discussionmentioning

confidence: 99%

General Relativistic Radiation MHD Simulations of Supercritical Accretion onto a Magnetized Neutron Star: Modeling of Ultraluminous X-Ray Pulsars

Takahashi

Ohsuga

2017

ApJL

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By performing 2.5-dimensional general relativistic radiation magnetohydrodynamic simulations, we demonstrate supercritical accretion onto a non-rotating, magnetized neutron star, where the magnetic field strength of dipole fields is 10 10 G on the star surface. We found the supercritical accretion flow consists of two parts; the accretion columns and the truncated accretion disk. The supercritical accretion disk, which appears far from the neutron star, is truncated at around ≃ 3R * (R * = 10 6 cm is the neutron star radius), where the magnetic pressure via the dipole magnetic fields balances with the radiation pressure of the disks. The angular momentum of the disk around the truncation radius is effectively transported inward through magnetic torque by dipole fields, inducing the spin up of a neutron star. The evaluated spin up rate, ∼ −10 −11 s s −1 , is consistent with the recent observations of the ultra luminous X-ray pulsars. Within the truncation radius, the gas falls onto neutron star along dipole fields, which results in a formation of accretion columns onto north and south hemispheres. The net accretion rate and the luminosity of the column are ≃ 66L Edd /c 2 and 10L Edd , where L Edd is the Eddington luminosity and c is the light speed. Our simulations support a hypothesis whereby the ultra luminous X-ray pulsars are powered by the supercritical accretion onto the magnetized neutron stars.

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“…These global simulations confirm many properties of the slim disk model. Particularly, strong radiation-driven outflows are formed in these simulations (Watarai & Fukue 1999;Ohsuga & Mineshige 2014).…”

Section: Introductionmentioning

confidence: 89%

“…However, radiative driven outflow from the slim disks has been expected for a long time (Watarai & Fukue 1999). Figure 8 shows that at each radius, when the height z becomes comparable to radius r, gravitational acceleration starts to drop with height and becomes systematically smaller than radiation acceleration.…”

Section: Comparison With the Slim Disk Modelmentioning

confidence: 99%

A Global Three-Dimensional Radiation Magneto-Hydrodynamic Simulation of Super-Eddington Accretion Disks

Jiang

Stone

Davis

2014

ApJ

407

477

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We study super-Eddington accretion flows onto black holes using a global three-dimensional radiation magneto-hydrodynamical simulation. We solve the time-dependent radiative transfer equation for the specific intensities to accurately calculate the angular distribution of the emitted radiation. Turbulence generated by the magneto-rotational instability provides self-consistent angular momentum transfer. The simulation reaches inflow equilibrium with an accretion rate ∼220 L Edd /c 2 and forms a radiation-driven outflow along the rotation axis. The mechanical energy flux carried by the outflow is ∼20% of the radiative energy flux. The total mass flux lost in the outflow is about 29% of the net accretion rate. The radiative luminosity of this flow is ∼10 L Edd . This yields a radiative efficiency ∼4.5%, which is comparable to the value in a standard thin disk model. In our simulation, vertical advection of radiation caused by magnetic buoyancy transports energy faster than photon diffusion, allowing a significant fraction of the photons to escape from the surface of the disk before being advected into the black hole. We contrast our results with the lower radiative efficiencies inferred in most models, such as the slim disk model, which neglect vertical advection. Our inferred radiative efficiencies also exceed published results from previous global numerical simulations, which did not attribute a significant role to vertical advection. We briefly discuss the implications for the growth of supermassive black holes in the early universe and describe how these results provided a basis for explaining the spectrum and population statistics of ultraluminous X-ray sources.

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Radiative Disk Winds from a Self-Similar Slim Disk

Cited by 87 publications

References 13 publications

The influence of large-scale magnetic field in the structure of supercritical accretion flow with outflow

The influence of large-scale magnetic field in the structure of supercritical accretion flow with outflow

General Relativistic Radiation MHD Simulations of Supercritical Accretion onto a Magnetized Neutron Star: Modeling of Ultraluminous X-Ray Pulsars

A Global Three-Dimensional Radiation Magneto-Hydrodynamic Simulation of Super-Eddington Accretion Disks

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