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Questions tagged [accretion-disk]

An accretion disk is the disk around a compact star that accumulates matter from e.g. a companion star by the Roche lobe overflow or stellar wind transfer.

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What angle would frame dragging shove matter in the innermost accretion disk relative to the equatorial plane or orbit?

I understand that frame dragging will imbue momentum on plasma orbiting a black hole at close range. My first question is - is this kinetic energy inserted very narrowly relative to the equatorial ...
Khannea's user avatar
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Does a white hole forms accretion disk?

A white is time reversal of a blackhole at least mathematically, I know it can't exist but may I know if it can form accretion disc similar to those stellar mass black holes. Does it spins on it's ...
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Should we expect lightning-like phenomena as matter enters the accretion disk of a black hole?

As matter enters the accretion disk it will rapidly turn into superheated plasma. I would expect this to coincide with lightning-like phenomena due to the electric potential difference between this ...
Logan J. Fisher's user avatar
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Would an ionized accretion disk experience radial charge separation?

(Sorry if I'm using the wrong terms, but I've yet to find any search terms that seem related to what I'm thinking of. If I did know what to search for, I wouldn't be asking this question.) Would an ...
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Perfect Conducting (PC) and Perfect Insulating (PI) boundary conditions for magnetic induction in MHD problems in cylindrical coordinates

I understand the computational implementation of the PC and PI bcs in cartesian case. In terms of the magnetic field components for PI, we have $B_x = B_y = B_z = 0$, and for PC, we have $B_x = \...
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Are these star - black hole binary pair illustrations art or physics?

It seems that every illustration of a black hole pulling matter off a star looks like this one from the Chandra X-ray Observatory website. Or this one from Nature - Two black holes found in a star ...
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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 ...
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Can stars gravitationally shield a black hole?

Is it possible to arrange a set of massive objects such as stars in orbit around a black hole such that objects of lesser mass cannot physically reach and fall into the event horizon of the black hole?...
Gopal Anantharaman's user avatar
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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 ...
哲煜黄's user avatar
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Star gets eaten and spit out?

How does material get swallowed and torn apart by a black hole and have its light vanish. But somehow the same material escapes years later. After its light couldn't even escape? They watched it for ...
Justin Dougherty's user avatar
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How would the Redshift of a Photon be influenced if it travels through a volumetric gas disk?

so me and a buddy have been working on a Black Hole render engine for quiet a while now. And at this point we have most of the technical stuff worked out. Which results in images like these; Note, ...
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Why is the common envelope ejected in some accretor-donor systems?

As an example, let us consider a binary system of a neutron star and an evolved star (e.g. red giant) that has expanded, filled its roche lobe, and started the mass transfer onto the neutron star. ...
Gianluca's user avatar
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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 ...
Árpád Szendrei's user avatar
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What does a black hole accretion disk look like edge on?

We have images of two black holes so far, with representations showing a deep black center where in-falling matter vanishes- how would that look side on? Would it be possible to even obtain an image ...
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What determines the black hole accretion rate?

There is clearly a natural timescale to accrete matter around a black hole given by the balance of pressure and gravity, known as the Eddington luminosity. However, as I understand it, this is really ...
Guy's user avatar
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Rotating black hole

I know that everything that is shaped from gravity force is rotating, and gravity is a central force. but I want to know how can we detect that a black hole has an angular momentum? By which ...
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Neutrinos and black holes

As a new user I could not comment on Do neutrinos of any flavor get trapped in black holes? My question is that the Ice Cube facility has mapped Neutrinos coming from black holes, as stated in ...
Adrian Morrish's user avatar
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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 ...
Sean Holloway's user avatar
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If the BH accretion disk rotates near the speed of light should its EM-radiation in direction of rotation be highly blueshifted?

If the BH accretion disk rotates near the speed of light should its EM-radiation in direction of rotation be highly blueshifted? Maybe gamma blushifted if there weren't gravitational redshift?
Krešimir Bradvica's user avatar
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Circular gravitational field

Why do all heavy masses in the universe always have circular gravitational field and why do objects 'falling' under their spacetime influence always fall in circles? For example, accretion disks ...
Scientific Co 's user avatar
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Would a black hole act as a particle accelerator between the photon sphere and the event horizon?

I'm trying to understand the behavior of photons between the photon sphere and the event horizon. Here is what I think I understand so far : the radius of the PS is 1.5 times the Schwarzschild radius ...
Inbouto's user avatar
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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?
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What happens when a cool brown dwarf slowly accretes matter?

Let's imagine that we take a brown dwarf close to the minimum mass of a red dwarf. Then let's allow it a few quadrillion years to cool. Finally slowly accrete matter at a rate of say 1 Jupiter mass ...
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What happens when a helium white dwarf accretes enough matter?

What happens when a helium white dwarf accretes enough matter? Say you have a white dwarf made of helium, what happens when it's core becomes dense enough to fuse helium and how massive would it have ...
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Is a fusion process possible inside an accretion disk?

Is a fusion process possible inside an accretion disk? As the speed of matter inside an accretion disk approaches the speed of light can an incoming object collide with the disk material and cause a ...
Janko Bradvica's user avatar
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How can supersonic accretion flows exist in astrophysical scenarios?

I often hear about supersonic accretion flows in astrophysical scenarios: for example, the inner parts of the accretion disk around a supermassive black hole or cold filaments accreting into galaxies ...
quantumflash's user avatar
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Does some of accretion disk light make focal points above the black hole poles? [duplicate]

Does some of accretion disk light make focal points above the black hole poles?
Janko Bradvica's user avatar
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Does the latest picture of EHT mean the end to the no hair theorem?

I couldn't help but noticing what looks like "hair" in the latest image from EHT. Does this mean the end of the no hair theorem? Pun intended but also a serious question.
my2cts's user avatar
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What ranges of $l$ and $m$ give the spherical harmonics for disk features?

The spherical harmonics represent a spherically symmetric basis and correspond to the eigenfunction solutions of the three-dimensional Laplacian. They take the form $$ Y_l^m(\theta,\phi) = \sqrt{\frac{...
Joseph Farah's user avatar
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Are the particles in the accretion disk in free fall around the black hole?

I know that black hole can feed off the material in the accretion disk and gain mass, the accretion disk is also powered by the black hole to move at a fraction of speed of light. I am wondering are ...
user6760's user avatar
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Are there black holes without accretion disk but emitting astrophysical jets?

First a citation from Wikipedia page about relativistic jets: "Jets may also be observed from spinning neutron stars. An example is pulsar IGR J11014-6103, which has the largest jet so far ...
Janko Bradvica's user avatar
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Why does the jet come out perpendicular to the accretion disc?

Why does the jet always come out perpendicular to the plane of the accretion disc around a black hole?
Solidification's user avatar
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Is the Accretion Disk of a Black Hole just an illusion?

As a matter of fact, I recently learnt that as an object is approaching a black hole, to an outside observer the object seems to be getting slower and slower and will cross the event horizon after an ...
Aryan 's user avatar
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I have a couple of questions regarding the physics of planet Miller and the black hole it's orbiting from the movie "Interstellar" [closed]

I watched the movie and thoroughly enjoyed it. I had a couple of questions regarding the physics, so I looked for answers. I got them, but I was left even more questions. I know that a lot of these ...
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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 ...
Richard's user avatar
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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 ...
Richard's user avatar
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Physical importance of centrifugal force and Coriolis force in the context of the restricted 3-body problem

In the textbook Galactic Dynamics (Binney and Tremaine), the restricted three-body problem to find the trajectory of a test mass that orbits in the combined gravitational field of two masses $M$ and $...
Richard's user avatar
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What happens to the accretion disk when two black holes merge?

I'm aware that accretion disks around black holes are formed from the swirling mass of matter that is slowly being stripped of its atoms, but what happens to it when two black holes merge? I was ...
Pugs's user avatar
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AGN accretion disk double peak explained?

I have a question to the following lecture: https://ned.ipac.caltech.edu/level5/Fabian4/Fab2_2.html In Figure 3 it says that a narrow annuli of a Newtonian disk should alrdy show a double peak ...
Tobias Trust's user avatar
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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\...
Richard's user avatar
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Newtonian/Relativistic Solutions of Fluid Disks in orbit around a massive body

I have been trying to make an RMHD (Relativistic Magneto-Hydro Dynamics) Set-up of a Disk around a Massive Rotational Body. The initial paper I have been studing a paper which uses a Fishbone & ...
Billy Matlock's user avatar
3 votes
1 answer
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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 ...
AnnaD's user avatar
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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 ...
AnnaD's user avatar
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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-...
Hrishi's user avatar
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How can a gas be in circular orbit when centrifugal force is dominant in an accretion disk around a black hole?

In the textbook "Black Holes, White Dwarfs and Neutron Stars: The Physics of Compact Objects" by Shapiro and Teukolsky, the author makes the following statement while discussing the standard thin disk ...
Richard's user avatar
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Disk-like structures spectra vs ring spectra?

In the introduction to this paper (https://arxiv.org/abs/1803.06423) it is mentioned that disk-like spectra was observed in black hole X-ray binaries, when models would expected to be unstable (...
Maxtron Moon's user avatar
3 votes
2 answers
180 views

What causes the heating of a black hole's accretion disk?

Sheperd Doeleman said in a TED video that the accretion disk is heated by friction. Is that correct? I thought it might be adiabatic heating from the compression of the gasses.
Doradus's user avatar
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Can Compton scattering increase a photon's energy?

I've read (in Hagai Netzer's book The Physics and Evolution of Active Galactic Nuclei) that "Comptonization in the [black hole's accretion] disk atmosphere can increase the energy of some photons..." [...
Jim421616's user avatar
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Understanding the notion of lose or win of angular momentum in accretion disk

Here is below a slide of one of my lecture in planetology : I understand well the fact that ring A will be slow down by friction with ring B since ring B is rotating slower and the inverse process (...
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Wind-fed Accretion and White Dwarf stars

Can a White Dwarf star in a binary system accrete matter via the Wind-fed accretion process?
LightningStrike's user avatar