APOD: Visualization: A Black Hole Disk... (2024 May 08)

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APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by APOD Robot » Wed May 08, 2024 4:05 am

Image Visualization: A Black Hole Accretion Disk

Explanation: What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization. The video starts with you, the observer, looking toward the black hole from just above the plane of the accretion disk. Surrounding the central black hole is a thin circular image of the orbiting disk that marks the position of the photon sphere -- inside of which lies the black hole's event horizon. Toward the left, parts of the large main image of the disk appear brighter as they move toward you. As the video continues, you loop over the black hole, soon looking down from the top, then passing through the disk plane on the far side, then returning to your original vantage point. The accretion disk does some interesting image inversions -- but never appears flat. Visualizations such as this are particularly relevant today as black holes are being imaged in unprecedented detail by the Event Horizon Telescope.

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by AVAO » Wed May 08, 2024 5:44 am

APOD Robot wrote: Wed May 08, 2024 4:05 am Image Visualization: A Black Hole Accretion Disk

Explanation: What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization. The video starts with you, the observer, looking toward the black hole from just above the plane of the accretion disk. Surrounding the central black hole is a thin circular image of the orbiting disk that marks the position of the photon sphere -- inside of which lies the black hole's event horizon. Toward the left, parts of the large main image of the disk appear brighter as they move toward you. As the video continues, you loop over the black hole, soon looking down from the top, then passing through the disk plane on the far side, then returning to your original vantage point. The accretion disk does some interesting image inversions -- but never appears flat. Visualizations such as this are particularly relevant today as black holes are being imaged in unprecedented detail by the Event Horizon Telescope.

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...Well. After yesterday's illustration, I thought it couldn't get any worse. But of course it happens as it has to...

"This movie shows a complete revolution around a simulated black hole and its accretion disk following a path that is perpendicular to the disk."

You can also animate illustrations. "A simulated black hole" implies that it is a "scientific" simulation, even though the title "Black Hole Accretion Disk Visualization" ONLY talks about a visualization. but ok... at least it still looks pretty nice as a visualisation.

As I said, I'm only interested in "real" pictures, which in this case is a real challenge since there aren't any like that here.

First, to understand today's APOD animation.
The first image of a black hole comes from M87 in April 2017. This was only published in April 2019. So almost two years later.
One of the main reasons for this was, among other things, the questions of how to a) interpret and b) visualize the collected data. The first image (as seen above) is the result of a statistical assessment of around 100 generated variants. That is, it was considered most likely that the black hole of M87 could look like this. In other words, the various scientific teams that worked in competition to interpret the data came to the conclusion that the selected variant, based on the analysis, represented the data collected most realistically. So everything was done correctly and completely ok.

What interested me, of course, were the remaining 99 variants. If you superimpose these to get an image that is the integral of all possibilities:
What was even more visible here than in the original image is the various "drains" on the outside.
This topic of "drains" is currently not “yet” discussed scientifically.

What is interesting, in the following picture from yesterday, is the fact that at M87 only the jet directed against us is visible, and the opposite jet, which also exists, is only slightly visible very close to the black hole. But there in the form of two strands.
The fact that the two opposing jets each effectively break up from two helical, twisting partial jets is clearly visible in the following image.
This might explain why up to four drains from the black hole can be visible.
But here too it is just a theory...


Well, back to the starting point. The first image of a black hole also raised the question of why it looks exactly as expected: black and round. (Why black and not white is a different topic...) But why is it so beautifully round on the inside? If one assumes that, according to theory, every black hole also has an accretion disk, an observation exactly from the polar axis would be pure coincidence.

I think that this question was one of the reasons why NASA commissioned their visualisation office to create this visualisation shortly after the publication of the first image (color analogies are purely coincidental). This is in order to better illustrate the scientific explanatory model for this problem.

The animation must also show that the near field of a black hole behaves physically completely differently than the "mechanistically" based behavior of the wider environment.

jac berne (flickr) NGC 383

Since the black hole is constantly changing its polar axis and rotating,
It is to be expected that the wider environment will also be “pulled along” in the direction of rotation.
jac berne (flickr) NGC 3607

In the near field, the kind of space has a completely different behavior.
This is what the animation should show.

Interestingly, the corresponding black hole image from our own galaxy shows virtually the same appearance.
at least the one that was selected ;-)

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Foizman » Wed May 08, 2024 10:32 am

Even if it does not correspond to reality:
It would be easier for an intuitive idea of the animation if the "top" and the "bottom" of the accredation disc had different colors, i.e. false colors.

Then it would be easier to follow the visualization of where the top and bottom are when you look at the disc from the side and move around.

Just as a suggestion...

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Christian G. » Wed May 08, 2024 12:17 pm

I thought that a visualization such as this one only shows the theoretical anatomy of a black hole, but if we sent actual observers all around the black hole and asked them what they saw, they would all report the same thing! No matter where you stand around a black hole, it will eerily appear as facing you! But I may have misunderstood...

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Chris Peterson » Wed May 08, 2024 12:58 pm

AVAO wrote: Wed May 08, 2024 5:44 am If one assumes that, according to theory, every black hole also has an accretion disk...
What theory is that? I think the overwhelming majority of black holes in the Universe have no accretion disk.

This simulation shows the appearance of a black hole with an accretion disk. Simulations have also been made showing black holes without them, where we see only the odd lensing of the background stars.
Chris

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Christian G. » Wed May 08, 2024 1:32 pm

On the topic of visualizations, Jean-Pierre Luminet is a French astrophysicist who made this image of a black hole 45 YEARS AGO! The first one ever apparently. Using maths, and a 1970’s computer… He’s still alive and still studying black holes today, he deserves a mention on this black hole week! (I've added the APOD to compare)
L.jpg
apod.png
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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by jeffryfisher » Wed May 08, 2024 3:22 pm

I'm curious about the reddish coloring of the accretion disk. Was that an artistic choice or a scientific expectation? I ask because I've read that black hole (systems) shine in X-rays, suggesting that even after gravitational red-shifting, they emit wavelengths more energetic than red. Might the disk appear white (or even bluish-white) to an outside observer?

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Ann » Wed May 08, 2024 4:43 pm

AVAO wrote: Wed May 08, 2024 5:44 am
APOD Robot wrote: Wed May 08, 2024 4:05 am Image Visualization: A Black Hole Accretion Disk

Explanation: What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization. The video starts with you, the observer, looking toward the black hole from just above the plane of the accretion disk. Surrounding the central black hole is a thin circular image of the orbiting disk that marks the position of the photon sphere -- inside of which lies the black hole's event horizon. Toward the left, parts of the large main image of the disk appear brighter as they move toward you. As the video continues, you loop over the black hole, soon looking down from the top, then passing through the disk plane on the far side, then returning to your original vantage point. The accretion disk does some interesting image inversions -- but never appears flat. Visualizations such as this are particularly relevant today as black holes are being imaged in unprecedented detail by the Event Horizon Telescope.

<< Previous APOD This Day in APOD Next APOD >>
...Well. After yesterday's illustration, I thought it couldn't get any worse. But of course it happens as it has to...

"This movie shows a complete revolution around a simulated black hole and its accretion disk following a path that is perpendicular to the disk."

You can also animate illustrations. "A simulated black hole" implies that it is a "scientific" simulation, even though the title "Black Hole Accretion Disk Visualization" ONLY talks about a visualization. but ok... at least it still looks pretty nice as a visualisation.

As I said, I'm only interested in "real" pictures, which in this case is a real challenge since there aren't any like that here.

First, to understand today's APOD animation.
The first image of a black hole comes from M87 in April 2017. This was only published in April 2019. So almost two years later.
One of the main reasons for this was, among other things, the questions of how to a) interpret and b) visualize the collected data. The first image (as seen above) is the result of a statistical assessment of around 100 generated variants. That is, it was considered most likely that the black hole of M87 could look like this. In other words, the various scientific teams that worked in competition to interpret the data came to the conclusion that the selected variant, based on the analysis, represented the data collected most realistically. So everything was done correctly and completely ok.

What interested me, of course, were the remaining 99 variants. If you superimpose these to get an image that is the integral of all possibilities:
What was even more visible here than in the original image is the various "drains" on the outside.
This topic of "drains" is currently not “yet” discussed scientifically.

What is interesting, in the following picture from yesterday, is the fact that at M87 only the jet directed against us is visible, and the opposite jet, which also exists, is only slightly visible very close to the black hole. But there in the form of two strands.
The fact that the two opposing jets each effectively break up from two helical, twisting partial jets is clearly visible in the following image.
This might explain why up to four drains from the black hole can be visible.
But here too it is just a theory...


Well, back to the starting point. The first image of a black hole also raised the question of why it looks exactly as expected: black and round. (Why black and not white is a different topic...) But why is it so beautifully round on the inside? If one assumes that, according to theory, every black hole also has an accretion disk, an observation exactly from the polar axis would be pure coincidence.

I think that this question was one of the reasons why NASA commissioned their visualisation office to create this visualisation shortly after the publication of the first image (color analogies are purely coincidental). This is in order to better illustrate the scientific explanatory model for this problem.

The animation must also show that the near field of a black hole behaves physically completely differently than the "mechanistically" based behavior of the wider environment.

jac berne (flickr) NGC 383

Since the black hole is constantly changing its polar axis and rotating,
It is to be expected that the wider environment will also be “pulled along” in the direction of rotation.
jac berne (flickr) NGC 3607

In the near field, the kind of space has a completely different behavior.
This is what the animation should show.

Interestingly, the corresponding black hole image from our own galaxy shows virtually the same appearance.
at least the one that was selected ;-)
Superb images, Jac! I love your contributions to this forum.

You made me interested in NGC 383, an elliptical/lenticular radio galaxy with a radio jet:


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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by johnnydeep » Wed May 08, 2024 6:07 pm

There's far too much here for me to understand, but I'll ask this question: what's the difference between the event horizon and the photons sphere, and why it the photon sphere 50% larger than the event horizon? At least that's what I'm seeing at Wikipedia:
https://en.wikipedia.org/wiki/Photon_sphere wrote:
A photon sphere[1] or photon circle[2] is an area or region of space where gravity is so strong that photons are forced to travel in orbits, which is also sometimes called the last photon orbit.[3] The radius of the photon sphere, which is also the lower bound for any stable orbit, is, for a Schwarzschild black hole,

𝑟 = 3 GM/c2 = ³⁄₂ rs

where G is the gravitational constant, M is the mass of the black hole, c is the speed of light in vacuum, and rs is the Schwarzschild radius (the radius of the event horizon); see below for a derivation of this result.
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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by AVAO » Wed May 08, 2024 6:53 pm

Christian G. wrote: Wed May 08, 2024 1:32 pm On the topic of visualizations, Jean-Pierre Luminet is a French astrophysicist who made this image of a black hole 45 YEARS AGO! The first one ever apparently. Using maths, and a 1970’s computer… He’s still alive and still studying black holes today, he deserves a mention on this black hole week! (I've added the APOD to compare)

L.jpgapod.png
Insightful comparison. No comment ;-)

"Numerical simulations made with Jean-Alain Marck in 1989, using my 1979 calculations but adding false colors and variable viewing angles (starting from 0° for an equatorial view to 90° for a polar one), thanks to the progress of computers at the time." Jean-Pierre Luminet


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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by AVAO » Wed May 08, 2024 7:14 pm

Chris Peterson wrote: Wed May 08, 2024 12:58 pm
AVAO wrote: Wed May 08, 2024 5:44 am If one assumes that, according to theory, every black hole also has an accretion disk...
What theory is that? I think the overwhelming majority of black holes in the Universe have no accretion disk.

This simulation shows the appearance of a black hole with an accretion disk. Simulations have also been made showing black holes without them, where we see only the odd lensing of the background stars.
OK, right. Good point. The following formulation would probably have been better:
...every black hole also has an accretion disk,at some point in his life...

I think it is true that there is a close connection between the density of matter in the environment, the shape of the accretion disk, the speed of rotation of the black hole and the intensity of the bipolar jets. If the density of matter in the environment is too low, the entire mechanism will not work at all. I therefore don't think there are many dried-out SMBHs that can survive for long.

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by AVAO » Wed May 08, 2024 8:53 pm

Ann wrote: Wed May 08, 2024 4:43 pm
AVAO wrote: Wed May 08, 2024 5:44 am

jac berne (flickr) NGC 383

Superb images, Jac! I love your contributions to this forum.

You made me interested in NGC 383, an elliptical/lenticular radio galaxy with a radio jet:


Ann
ThanX Ann

Yes. I like them too!

Jac

Pic1 NGC 383 and NGC 315: jac berne (flickr) LOFAR Survey (VLA:RADIO)

Pic2 NGC 383: jac berne (flickr) NRAO (VLA:RADIO)

Click to view full size image 1 or image 2
Pic3 NGC 383: jac berne (flickr) NRAO (VLA:RADIO) / NASA/ESA (HST)

Pic4 NGC 383: jac berne (flickr) NRAO (VLA:RADIO) / NASA/ESA (HST)

Pic 5 NGC 383: jac berne (flickr) NRAO (VLA:RADIO) / NASA/ESA (HST)


NGC 383 (3C31) has a supermassive hole between 290 million and 1.3 billion solar masses, which isn't exactly accurate.
In the first image (Pic 1) you can also see NGC 315 at the bottom right. Another radioactive galaxy with a supermassive hole of 43 to 180 million solar masses. Both exhibit massive jets and evidence of high rotational speeds and accretion disks.

Interesting: While in NGC 315 it appears that the jet of the black hole is practically perpendicular to the galactic disk, it (and thus also the axis of the black hole) appears in NGC 383 to be strongly inclined to the galactic disk.

NRAO (VLA)

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Ann » Fri May 10, 2024 3:42 am

AVAO wrote: Wed May 08, 2024 8:53 pm Pic1 NGC 383 and NGC 315: jac berne (flickr) LOFAR Survey (VLA:RADIO)



NGC 383 (3C31) has a supermassive hole between 290 million and 1.3 billion solar masses, which isn't exactly accurate.
In the first image (Pic 1) you can also see NGC 315 at the bottom right. Another radioactive galaxy with a supermassive hole of 43 to 180 million solar masses. Both exhibit massive jets and evidence of high rotational speeds and accretion disks.

Interesting: While in NGC 315 it appears that the jet of the black hole is practically perpendicular to the galactic disk, it (and thus also the axis of the black hole) appears in NGC 383 to be strongly inclined to the galactic disk.

NRAO (VLA)

Jac, I had written a reply to you, and then I forgot to submit it! Stupid!!!

But once again, thank you for your gorgeous images. And thank you so much for calling my attention not only to NGC 383, but to NGC 315 as well! Imagine, two radio galaxies with humongous black holes and fantastic jets so close to one another! :shock: :D Because, yes, NGC 383 and NGC 315 are not only close to one another in the sky, but they have very similar radial velocities, too, so they are indeed close to one another for real!

So, once more, thank you for your gorgeous, gorgeous images, and thank you for pointing out things that many of most of us had missed! :D

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Re: APOD: Visualization: A Black Hole Disk... (2024 May 08)

Post by Astro_mark » Tue May 14, 2024 7:17 pm

It's amazing how we were able to get these images. I dread to think what we can achieve in 10 or 20 years!