Black hole breakthrough: New insight into mysterious jets

January 10, 2018 by Kayla Stoner, Northwestern University
Credit: Northwestern University

Through first-of-their-kind supercomputer simulations, researchers, including a Northwestern University professor, have gained new insight into one of the most mysterious phenomena in modern astronomy: the behavior of relativistic jets that shoot from black holes, extending outward across millions of light years.

Advanced simulations created with one of the world's most powerful supercomputers show the jets' streams gradually change direction in the sky, or precess, as a result of space-time being dragged into the rotation of the black hole. This behavior aligns with Albert Einstein's predictions about extreme gravity near rotating , published in his famous theory of general relativity.

"Understanding how rotating black holes drag the space-time around them and how this process affects what we see through the telescopes remains a crucial, difficult-to-crack puzzle," said Alexander Tchekhovskoy, assistant professor of physics and astronomy at Northwestern's Weinberg College of Arts and Sciences. "Fortunately, the breakthroughs in code development and leaps in supercomputer architecture are bringing us ever closer to finding the answers."

The study, published in the Monthly Notices of the Royal Astronomical Society, is a collaboration between Tchekhovskoy, Matthew Liska and Casper Hesp. Liska and Hesp are the study's lead authors and graduate students at The University of Amsterdam, Netherlands.

Rapidly spinning black holes not only engulf matter but also emit energy in the form of . Similar to how water in a bathtub forms a whirlpool as it goes down a drain, the gas and magnetic fields that feed a swirl to form a rotating disk—a tangled spaghetti of mixed into a broth of hot gas. As the black hole consumes this astrophysical soup, it gobbles up the broth but leaves the magnetic spaghetti dangling out of its mouth. This makes the black hole into a kind of launching pad from which energy, in the form of relativistic jets, shoots from the web of twisted magnetic spaghetti.

This simulation produced using the Blue Waters supercomputer is the first simulation ever to demonstrate that relativistic jets follow along with the precession of the tilted accretion disk around the black hole. At close to a billion computational cells, it is the highest resolution simulation of an accreting black hole ever achieved. Credit: Northwestern University

The jets emitted by black holes are easier to study than the black holes themselves because the jets are so large. This study enables astronomers to understand how quickly the jet direction is changing, which reveals information about the black hole spin as well as the orientation and size of the rotating disk and other difficult-to-measure properties of .

Whereas nearly all previous simulations considered aligned disks, in reality, most galaxies' central supermassive black holes are thought to harbor tilted disks—meaning the disk rotates around a separate axis than the black hole itself. This study confirms that if tilted, disks change direction relative to the black hole, precessing around like a spinning top. For the first time, the simulations showed that such tilted disks lead to precessing jets that periodically change their direction in the sky.

An important reason precessing jets were not discovered earlier is that 3-D simulations of the region surrounding a rapidly spinning black hole require an enormous amount of computational power. To address this issue, the researchers constructed the first black hole simulation code accelerated by graphical processing units (GPUs). A National Science Foundation grant enabled them to carry out the simulations on Blue Waters, one of the largest supercomputers in the world, located at the University of Illinois.

The confluence of the fast code, which efficiently uses a cutting-edge GPU architecture, and the Blue Waters supercomputer allowed the team to carry out simulations with the highest resolution ever achieved - up to a billion computational cells.

"The high resolution allowed us, for the first time, to ensure that small-scale turbulent disk motions are accurately captured in our models," Tchekhovskoy said. "To our surprise, these motions turned out to be so strong that they caused the disk to fatten up and the disk precession to stop. This suggests that precession can come about in bursts."

A comparison of a low resolution simulation (left) to the high-resolution simulation produced using Blue Waters (right) shows the effect of resolution on tilted accretion models. The high resolution model shows that precession and alignment slow down as a result of disk expansion due to magnetic turbulence.

Because accretion onto black holes is a highly complex system akin to a hurricane, but located so far away we cannot discern many details, simulations offer a powerful way of making sense of telescope observations and understanding the behavior of black holes.

The results are important for further studies involving rotating black holes, which are currently being conducted all over the world. Through these efforts, astronomers are attempting to understand recently discovered phenomena such as the first detections of gravitational waves from neutron star collisions and the accompanying electromagnetic fireworks as well as regular stars being engulfed by supermassive black holes.

The calculations also are being applied to interpreting the observations of the Event Horizon Telescope (EHT), which captured the first recordings of the supermassive black hole shadow in the center of the Milky Way.

Additionally, the jets' precession could explain fluctuations in the intensity of light coming from around black holes, called quasi-periodic oscillations (QPOs). Such oscillations can occur similarly to the way in which the rotating beam of a lighthouse increases in intensity as it passes by an observer. QPOs were first discovered near black holes (as X-rays) in 1985 by Michiel van der Klis (University of Amsterdam), who is a co-author of the new article.

Explore further: the geometry of nuclear black hole accretion disks

More information: M Liska et al. Formation of precessing jets by tilted black hole discs in 3D general relativistic MHD simulations, Monthly Notices of the Royal Astronomical Society: Letters (2017). DOI: 10.1093/mnrasl/slx174

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36 comments

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Chris_Reeve
Jan 10, 2018
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ursiny33
1 / 5 (5) Jan 10, 2018
The black holes collect every free electron near them, and those it releases by the destruction of atoms in high speed kinetic collisions in its material captures in orbit around the mass , a magnetic field of orbiting electrons held by gravity, that is what forms the containment vessel of the jets super structure in its outflows
Nik_2213
4.6 / 5 (9) Jan 10, 2018
#CR, have you missed the detail that these super-massive central black holes tend to jet 'normal' ie 'out of plane' of galaxy ? This does not affect the vast disk beyond second-order effects linked to ballistic in-falling and gravity sling-shots, showing gravity rules the rest of galaxy's motions ?

Again, your EU hypothesis seems to lack meaningful thought. Else, please show working ??
Chris_Reeve
Jan 10, 2018
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Chris_Reeve
Jan 10, 2018
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Chris_Reeve
Jan 10, 2018
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Parsec
4.3 / 5 (11) Jan 10, 2018
@mackita - Actually, asymmetric jet appearance is evidence that jet direction has changed over time. That observation by itself doesn't imply evidence of why the direction changes. This simulation does that. Also, black holes lose mass in tiny amounts due to Hawking radiation, but the infall of matter exceeds that tiny gain by many orders of magnitude for any black hole larger than about the size of a terrestrial mountain.

I can promise you that nothing occuring at the center of the galaxy is going to affect the terrestrial climate in any way. Doh!
PTTG
3 / 5 (4) Jan 10, 2018
I was going to complain about electric universe cultishness, but then I remembered that there are bigger problems.
Chris_Reeve
Jan 10, 2018
This comment has been removed by a moderator.
Captain Stumpy
4.4 / 5 (20) Jan 11, 2018
@chris/hannes the pseudoscience cult sock
The Electric Universe is simply the application of laboratory plasma physics principles to cosmic plasmas
wrong
if the eu accepted laboratory plasma physics, they would accept MR
they do not, and they continually state reconnection is pseudoscience regardless of the multiple world labs full of electrical engineers proving them wrong

more to the point: if they were in any way a scientific theory they would abide by the strict conventions of the scientific method
there are no predictions, there is no science

when they tried to make testable claims, they were proven to be not only idiots but so far off the mark due to ignorance (and religious fanatical fervour) that they stopped attempting to make any testable claims at all, other than after the fact claims and opinions of real science

that is the very definition of pseudoscience

therefore it is not application, laboratory plasma physics or even science
Da Schneib
4.5 / 5 (15) Jan 11, 2018
Important to note here that this doesn't affect the origin of jets, and it's not an explanation for them; it just predicts that if the accretion disk is tilted, the jets will precess. And that's just what we see.
Da Schneib
4.1 / 5 (13) Jan 11, 2018
Even more interesting here is that this is gravitomagnetism. This is not electromagnetism; it's the magnetism-like effects of gravity, the same sort of thing that results in deSitter and Lense-Thirring effects.
Chris_Reeve
Jan 11, 2018
This comment has been removed by a moderator.
Chris_Reeve
Jan 11, 2018
This comment has been removed by a moderator.
yep
1.8 / 5 (19) Jan 11, 2018
@captain consensus stooge
Pseudoscience is the un falisifiable physics defying nonsense based in a priori which was concocted before we had instruments in space.
The religious fanaticism is in your devotion to modern cosmologies endless garbage in garbage out mantra.
Captain Stumpy
4.2 / 5 (5) Jan 11, 2018
@idiot pseudoscience eu cult devotee yep
Pseudoscience is the un falisifiable physics defying nonsense based in a priori which was concocted before we had instruments in space
funny thing about science is: it's self correcting

if the idiot eu had the ability to prove, using science and evidence, that said "nonsense based in a priori" was in fact false, then they would be able to produce evidence that can be validated

they haven't because they are the ones making the "nonsense based in a priori" solely baesed upon their belief in a few people's comments which have been repeatedly proven false (you know, like: astrophysicists don't know plasma physics - or - reconnection is pseudoscience)

so what is proven at this point is that the eu can't do science, yet they still fanatically defend their position as being correct... much like ISIS defends their belief or x-tians defend theirs

the only difference between eu and ISIS is: the tract they follow
Merrit
5 / 5 (6) Jan 11, 2018
@CR well, suppose for one second that electric universe is correct. Then, why are we not detecting these electric fields? You say the orbits etc. are being determined by the electric force rather than gravity, yet we are not detecting it at all. Objects need to have a net positive or negative charge to be affected by electric fields in any meaningful way. Your theory makes absolutely no sense when compared to the observations we make of the universe.
Fractal_Plenum
not rated yet Jan 11, 2018
This article mentions "one of the most mysterious phenomena in modern astronomy: the behavior of relativistic jets". The environment in which these amazingly energetic jets are observed is one described as "a tangled spaghetti of magnetic field lines mixed into a broth of hot gas", which is a rather imprecise way of referring to a coherent filamentary plasma structure with evident magnetic fields throughout.

The approach of this research is rigorously deductive, i.e. supercomputer simulations. In contrast to this, there is the inductive method of science we learn in school—the idea of formulating hypotheses inspired by observation and using mathematical approximations to quantitatively map the data. If we stress the inductive approach, we may ask: could we be overlooking observations that could help us solve the aforementioned mystery through the inductive reasoning of rational empiricism?

(Continues...)
Da Schneib
1 / 5 (1) Jan 11, 2018
@Fractal, we will need better telescopes to have any observations to apply induction to.
Fractal_Plenum
not rated yet Jan 11, 2018
(It won't let me paste the second part. It says it's spam when it clearly isn't.)
Merrit
5 / 5 (1) Jan 12, 2018
We don't really know anything about the composition of a black hole because we can't see them. There is no evidence that they are actually point masses. The closest thing we have for comparison is neutron stars. Neutron stars can have mass right up to the point where they would have been a black hole. These stars are very dense but there is no reason that a little extra mass that would tip them over the edge would cause it to collapse into a point mass. It is just unrealistic. Also, if there are any fermions still intact, they can't occupy the same space. Even though nothing can escape from a black hole it can still effect its surroundings through the forces of the universe such as the electromagnetic force. So, we may be able to induce it's structure to a degree from that.
Da Schneib
3 / 5 (4) Jan 12, 2018
@Merrit, the idea that black holes contain point masses is speculation. In fact, the size of a black hole is the size of its event horizon, in standard physics. If you want to speculate, go ahead, but keep in mind it has nothing to do with physics except as extrapolated into a realm where we have no data and don't expect to ever get any.
Merrit
not rated yet Jan 12, 2018
Well, if we could do experiments in the vicinity of a black hole I think we would be able to deduce some information about them. Only so much we can do with telescopes here on earth. For instance, by measuring changes in the force of gravity as you approach the black hole you might be able to deduce its density and determine if it is a point mass or not.
if black holes are creating magnetic fields do we even know if it is from the black hole itself or possibly generated from the accretion disk?

If the black holes are creating magnetic fields I find it unlikely that it could do that as a point mass.
jonesdave
3.2 / 5 (9) Jan 12, 2018
To our surprise, these motions turned out to be so strong that they caused the disk to fatten up and the disk precession to stop. This suggests that precession can come about in bursts
This is IMO correct insight and it can be also observed in Fermi data. The http://i.filmot.org/JRGgtSu.jpg that galactic core explosions recur about every 13,000 - 26,000 years for major outbursts which last for several hundred to a few thousand years.


I wouldn't take anything that La Violette says seriously. The supposed PhD dissertation isn't one. They have to be set out in a certain way. This isn't. Your link merely goes to a paper that has been placed on Arxiv, and never been submitted to a peer reviewed journal. Your 2nd link leads to a crackpot science site.
jonesdave
3.2 / 5 (9) Jan 12, 2018
here is also interesting aspect of barycenter of multibody system (galaxy or solar system), i.e. that the massive bodies tend to revolve it instead of some physical object at the center.


Nope. There are animations, based on years of telescope data, showing the orbits of the stars at the galactic centre. No way are they simply orbiting in a desultory fashion around the barycentre! These are highly elliptical orbits, all orbiting a single point in space. It is not difficult to work out the placement and mass of the unseen object, based on those numerous orbiting stars.
You can scour the (peer reviewed) scientific literature, and I doubt that you will find an alternative explanation for Sgr A*. I'm sure there are plenty of woo sites out there with all sorts of nonsense on them. However, who cares?
http://www.galact...ons.html

Da Schneib
4 / 5 (4) Jan 13, 2018
Worth considering: a black hole can have a charge. Black holes can spin. Therefore, a spinning black hole constitutes moving charges which means a magnetic field as moving charges always create. Therefore spinning charged black holes (i.e. Kerr-Newman metric black holes) have a magnetic field. Now, where they can acquire an electric charge is an interesting question.
milnik
2.3 / 5 (3) Jan 14, 2018
Again this is evidence that science did not understand the structure of the universe !!
In the universe, all made up of matter (MEEU), has the sequence of the cycle of forming all forms of matter, from subatomic particles (such as quarks), to the formation of the cluster of galaxies. These are the processes of the formation of celestial bodies, but the black holes do not belong to this sequence of processes. They do the reverse process that returns the matter back to the form of what it is formed from. This substance is AETHER, which fills the infinite universe. The "solid state" of matter with AETHER substance forms the appearance of GRAVITATION, which has the task of bringing matter into the masses of mass, until critical mass and critical gravity is achieved.
milnik
2.3 / 5 (3) Jan 14, 2018
Then the surrounding celestial bodies are "sucked" into that place (black hole). It is an area where gravity increases from the surrounding to the critical size. The one around BH can only be influenced by magnetism, because the mass is converted, first into plasma, and later to Aether, and the plasma has a very magnetic field, inversely proportional to a magnet or a pulsar (not as a magnet).
These jammers, if they exist, can be excited outside the horizon, which is the effect of a magnetic strong field on surrounding gases that are not sucked into BH.
Merrit
not rated yet Jan 14, 2018
@da schneib it is true even a point mass like an electron can have a magnetic moment. The equation is a bit different though for a sphere of radius r. We can figure out a black holes spin already. If we could get closer we could more accurately measure its mass, charge, and magnetic field. I believe that is everything we would need to determine either it's radius r or if it is really a point mass.
milnik
not rated yet Jan 14, 2018
@Merrit,Do you know why the electron has a magnetic moment and how do any particles get that MM? And while some claim that BH has a spin, it is evidence that they do not know what a black hole is.
Merrit
1 / 5 (1) Jan 14, 2018
@milnik I am not an expert, but from what I read the orbits of electrons couldn't account for all the magnetic field so they determined the electrons have some intrinsic value in addition that they call spin.

As for BHs, theoretical ones are point masses or singularities. Whether the black holes we see are actually point masses or not is not currently known, but theory says they should be. While I have no doubt a black hole with sufficient mass would become a point mass or singularity, there is no reason to believe the transition point from when light can escape its gravitational field to where it can't is also necessarily the transition point when the mass collapses into a point mass.
Total_Evidence
not rated yet Jan 14, 2018
These scientists are trying to explain the observed energetic jets in a coherent filamentary plasma structure with evident magnetic fields throughout. Interestingly, a plasmoid is a coherent filamentary plasma structure with evident magnetic fields throughout. We have been producing plasmoids in the laboratory for many decades now (See for example: Bostick, Experimental Study of Ionized Matter Projected across a Magnetic Field, 1956)

Even more curiously, when plasmoids in the lab reach a threshold density, they discharge, usually along their spin axis. These "jets" heat the plasma to extremely high energies. This process can be observed beautifully in the dense plasma focus device.

From laboratory experiments to cosmological distances, experiments, simulations, and observations strongly suggest the plasma follows the same physics everywhere.

The real mystery seems to be how we can keep overlooking these correlations between experimental data and astrophysical observations.
Merrit
1 / 5 (1) Jan 14, 2018
Also, relatively doesn't really do a good job of explaining black holes anyways. Proper time does not change for an object falling into a black hole. The issue is that as you cross the event horizon, time dilation would cause everything else in the universe to pass at an infinitely faster rate so that a second for you would be the life time of the universe for everything outside. So the question I have is how a black hole would even have the time to collapse into a singularity or spin when it takes an infinite amount of time for us for any amount of time to pass inside the event horizon. I would think our equations must be wrong and that it would actually take an infinite amount of mass to cause time dilation to be this extreme. I think the issue is we are combining two different phenomenon into the same thing.
Merrit
not rated yet Jan 14, 2018
Continued. We know time dilation is real based on things such as GPS satellites, but near an event horizon light has difficulty escaping and fails past the horizon. You could think of it as if the speed of light is actually slowing down near the horizon. In this case the slowing of time in comparison to us would be an illusion. Relatively is all about every frame of reference observing the same speed of light. The key part is observing. There can be both real parts and illusion parts to these observations. Relatively does not talk about what actually happens, but what we can actually observe.
Merrit
not rated yet Jan 14, 2018
Cont. when you look at an object under a microscope, it is not actually orders of magnitude larger, it just appears that way due to the light being distorted in this useful way. Well, light being given off from objects moving at relativistic rates or massive gravity is also being distorted. One good example of debate for real versus illusion is contraction due relativistic speeds. The contraction causes no stress on the object and the object can't even tell if it is being contracted, yet in particle physics it appears this contraction is real based on particle accelerators results.
milnik
3 / 5 (2) Jan 14, 2018
It's no wonder that science does not know many phenomena in the universe, when it does not understand the movement of celestial bodies and how the spin of these bodies creates. For this I have the proof with which I am correcting Kepler's laws, Kenig's theorem, Einstein's "proof" of the precession of the peripheral of the planet, I prove why our moon has always turned to the same side of the earth. In particular, it can be proved in the same way and how spin of all material particles is formed. We need to know that there are both material and energy particles (like gluons).

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