All Questions
Tagged with accretion-disk general-relativity
15
questions
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Space mission for experimental verification of frame-dragging in the strong-gravity limit
Frame-dragging is an important general relativistic effect that has been observed in the weak-field limit by the Gravity Probe B experiment for the gravitational field of the Earth.
Although the ...
- 2,015
4
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1
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Why don’t black rings exist in 3+1 dimensions?
In higher dimensions black holes can take different forms. Besides spheroids, there are also “black rings” which have a toroidal event horizon. However, in our 3+1 dimension no black ring solution has ...
- 1,455
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2
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356
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Why is the photon sphere spherical, but the accretion disk not?
As far as I understand, photons are massless, but are still subject to gravity, must follow the distortions of spacetime (including framedragging etc.), period.
Now the only answer on this site ...
- 29k
6
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Improving physics simulation of black hole accretion disk?
I have recently been working on software which uses ray tracing/marching to render a black hole in the Schwarzchild metric. I've implemented most everything that I originally set out to do, and I am ...
5
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2
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150
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Is accretion disc caused by frame dragging?
Is accretion disc around a Kerr black hole the result of its frame dragging?
- 1,161
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Some doubts regarding the Paczynsky-Wiita potential for modeling accretion disk around Schwarzschild black holes?
I am presently studying accretion processes around Schwarzschild black holes and for this purpose I am reading the classic paper by Paczynsky and Wiita (1980). In this paper, the authors define the ...
- 2,015
2
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48
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Is an exact description of accretion flow possible very close to a Schwarzschild black hole?
While modelling accretion disks around Schwarzschild black holes, various pseudo-Newtonian potentials are prescribed and then compared to general relativistic results. Though the pseudo-Newtonian ...
- 2,015
5
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658
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Effective potential for Kerr geometry
In the review Foundations of Black Hole Accretion Disk Theory, the authors defines an effective potential for Kerr geometry as (Chap. 2, eqn. 23)
$$\mathcal{U}_{eff}=-\frac{1}{2}\ln\left|g^{tt}-2lg^{t\...
- 2,015
3
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Physical significance of angular velocity of orbits around Kerr black holes
For the Kerr metric $$ds^2=\left(g_{tt}-\frac{g_{t\phi}^2}{g_{\phi\phi}}\right)dt^2+g_{\phi\phi}\left(d\phi-\omega dt\right)^2+g_{rr}dr^2+g_{\theta\theta}d\theta^2$$ the angular momentum is defined as ...
- 133
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What are Quasi-Periodic Oscilations and how can they be used to determine the mass of black holes?
Quasi-Periodic Oscillations (QPOs) are observed in almost all accreting systems and they provide an essential tool to explore accretion flows from compact objects.
But I couldn't understand what ...
- 133
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Four-momentum of a photon emitted from an accretion disk
Consider a non-rotating compact object surrounded by a revolving accretion disk. A distant observer sees the disk in an edge-on position. The center of the disk may be taken as the origin of $r-\theta-...
- 329
9
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Putting the importance of the blackhole image into perspective [closed]
The recent astonishing achievement of obtaining an actual image of a blackhole, resulted from a massive collaborative work using 8 different telescopes and the equally on par efforts in developing the ...
- 4,685
43
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3
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10k
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Why isn't the circumferential light around the M87 black hole's event horizon symmetric?
After the revelation of the first black hole images, it seems there is a bias towards the south side. Is it because of measuring it from earth or is it something more fundamental in the understanding ...
- 3,366
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How can write physics in terms of local rest frame?
Many times I saw that people wrote that we write the equations in terms of local rest frame, for example in the paper of Novikov and Thorne that calculated stress-energy tensor for Kerr blackhole ...
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2
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Accretion disks on neutron star binaries
Why does hydrogen gas from accretion disks not constantly get sucked onto/into a neutron star or into a black hole? I understand that some gets sucked into the black hole and some may come down and ...
- 268