Astrophysicists release IllustrisTNG, the most advanced universe model of its kind

February 1, 2018, Simons Foundation
Visualization of the intensity of shock waves in the cosmic gas (blue) around collapsed dark matter structures (orange/white). Similar to a sonic boom, the gas in these shock waves is accelerated with a jolt when impacting on the cosmic filaments and galaxies. Credit: IllustrisTNG collaboration

Novel computational methods have helped create the most information-packed universe-scale simulation ever produced. The new tool provides fresh insights into how black holes influence the distribution of dark matter, how heavy elements are produced and distributed throughout the cosmos, and where magnetic fields originate.

Led by principal investigator Volker Springel at the Heidelberg Institute for Theoretical Studies, astrophysicists from the Max Planck Institutes for Astronomy (MPIA, Heidelberg) and Astrophysics (MPA, Garching), Harvard University, the Massachusetts Institute of Technology (MIT), and the Flatiron Institute's Center for Computational Astrophysics (CCA) developed and programmed the new universe simulation model, dubbed Illustris: The Next Generation, or IllustrisTNG.

The model is the most advanced universe simulation of its kind, says Shy Genel, an associate research scientist at CCA who helped develop and hone IllustrisTNG. The simulation's detail and scale enable Genel to study how form, evolve and grow in tandem with their star-formation activity. "When we observe galaxies using a telescope, we can only measure certain quantities," he says. "With the simulation, we can track all the properties for all these galaxies. And not just how the galaxy looks now, but its entire formation history." Mapping out the ways galaxies evolve in the simulation offers a glimpse of what our own Milky Way galaxy might have been like when the Earth formed and how our galaxy could change in the future, he says.

Thin slice through the cosmic large-scale structure in the largest simulation of the IllustrisTNG project. The image brightness indicates the mass density and colour visualizes the mean gas temperature of ordinary ("baryonic") matter. The displayed region extends by about 1.2 billion light-years from left to right. The underlying simulation is presently the largest magneto-hydrodynamic simulation of galaxy formation, containing more than 30 billion volume elements and particles. Credit: IllustrisTNG collaboration

Mark Vogelsberger, an assistant professor of physics at MIT and the MIT Kavli Institute for Astrophysics and Space Research, has been working to develop, test and analyze the new IllustrisTNG simulations. Along with postdoctoral researchers Federico Marinacci and Paul Torrey, Vogelsberger has been using IllustrisTNG to study the observable signatures from large-scale magnetic fields that pervade the universe.

"The high resolution of IllustrisTNG combined with its sophisticated model allowed us to explore these questions of magnetic fields in more detail than with any previous cosmological simulations," says Vogelsberger, one of the authors of the three papers published today in the Monthly Notices of the Royal Astronomical Society.

Rendering of the gas velocity in a thin slice of 100-kiloparsec thickness (in the viewing direction), centered on the second most massive galaxy cluster in the TNG100 calculation. Where the image is black, the gas is hardly moving, while white regions have velocities which exceed 1,000 kilometers per second. The image contrasts the gas motions in cosmic filaments against the fast, chaotic motions triggered by the deep gravitational potential well and the supermassive black hole sitting at its center. Credit: IllustrisTNG collaboration

Modeling a (more) realistic universe

IllustrisTNG is a successor model to the original Illustris simulation developed by the same research team, but it has been updated to include some of the physical processes that play crucial roles in the formation and evolution of galaxies.

Like Illustris, the project models a cube-shaped universe smaller than our own. This time, the project followed the formation of millions of galaxies in a representative region of a universe with nearly 1 billion light-years per side (up from 350 million light-years per side just four years ago). lllustrisTNG is the largest hydrodynamic simulation project to date for the emergence of cosmic structures, says Springel, also of MPA and Heidelberg University.

The interstellar magnetic field strength: blue/purple shows regions of low magnetic energy arranged along filaments of the cosmic web, while orange and white show regions with significant magnetic energy inside halos and galaxies. Time evolution of the inside of a 10Mpc (comoving) region within TNG100-1 from the start of the simulation to z=0. Credit: The TNG Collaboration

The cosmic web of gas and dark matter predicted by IllustrisTNG produces galaxies quite similar to real galaxies in shape and size. For the first time, hydrodynamic simulations could directly compute the detailed clustering pattern of galaxies in space. In comparison with observational data - such as the data provided by the powerful Sloan Digital Sky Survey - the simulations from IllustrisTNG demonstrate a high degree of realism, says Springel.

In addition, the simulations predict how the cosmic web changes over time, especially in relation to the that underlies the cosmos. "It is particularly fascinating that we can accurately predict the influence of on the distribution of matter out to large scales," says Springel. "This is crucial for reliably interpreting forthcoming cosmological measurements."

Comparison of the distribution of intergalactic gas (mass), between TNG100-1 and Illustris-1. Low-density voids (black/dark blue) transition to cosmic filaments (yellow/green), gas halos (light blue) and individual galaxies (white). The time evolution of the exact same 10Mpc (comoving) region is compared between the two simulations, which distribute gas differently on large scales as a result of the differences in the galaxy formation models. Credit: The TNG Collaboration

Astrophysics via code and supercomputers

For the project, the researchers developed a particularly powerful version of their highly parallel moving-mesh code AREPO and used it on the Hazel Hen machine, Germany's fastest mainframe computer, at the High Performance Computing Center Stuttgart. To compute one of the two main simulation runs, the team employed more than 24,000 processors over the course of more than two months. "The new simulations produced more than 500 terabytes of data," says Springel. "Analyzing this huge mountain of data will keep us busy for years to come, and it promises many exciting new insights into different astrophysical processes."

Time evolution of a 10Mpc (comoving) cubic region, rendered from outside. The movie shows the gas temperature (blue: cold, green: warm: white: hot), comparing original Illustris (left) to TNG100 (right). In both cases, the rapid temperature fluctuations and outbursts around nodes in the cosmic web are due to various energetic "feedback" processes in the simulation. These include energy from stars (supernovae explosions) as well as heat and high-velocity winds from supermassive black holes. Credit: The TNG Collaboration

Supermassive black holes squelch star formation

In another study, Dylan Nelson, a researcher at MPA, was able to demonstrate the impact of black holes on galaxies. Star-forming galaxies shine brightly in the blue light of their young stars until a sudden evolutionary shift halts the star formation, so that the galaxy becomes dominated by old, red stars and joins a graveyard full of old and dead galaxies.

"The only physical entity capable of extinguishing the star formation in our large elliptical galaxies are the supermassive black holes at their centers," explains Nelson. "The ultrafast outflows of these gravity traps reach velocities up to 10 percent of the speed of light and affect giant stellar systems that are billions of times larger than the comparably small black hole itself."

Eight views: the evolving structure of a small 10Mpc region of cosmic space is visualized from TNG100-1. Each view shows a different output of the simulation (from left to right, top): gas matter density, dark matter density, stellar mass, magnetic field strength, (bottom) gas temperature, gas metallicity, the velocity field of the gas, and column density of OVI - the fifth ionization state of oxygen (O5+). Each view shows the same region of space, all of these components co-evolving together as the simulation runs. Credit: The TNG Collaboration

New findings for galaxy structure

IllustrisTNG also improves our understanding of the hierarchical structure of galaxy formation. Theorists argue that small galaxies should form first and then merge into ever-larger objects, driven by the relentless pull of gravity. The numerous galaxy collisions literally tear some galaxies apart and scatter their stars into wide orbits around the newly created large galaxies, which should give the galaxies a faint background glow of stellar light. These predicted pale stellar halos are very difficult to observe due to their low surface brightness, but IllustrisTNG was able to simulate exactly what astronomers should be looking for.

"Our predictions can now be systematically checked by observers," says Annalisa Pillepich, a researcher at MPIA, who led a further IllustrisTNG study. "This yields a critical test for the theoretical model of hierarchical galaxy formation."

The most massive cluster of TNG300 at z=0 (with a halo mass of ~ 1015 times the mass of the sun). Fixed in time, the video slowly rotates in space to show the structure from different view points. Each of the four panels shows the same predicted X-ray emission (in background color), while the overlaid contours show the predicted synchrotron emission, as would be observed by one of four radio telescopes: VLA, LOFAR, ASKAP, or SKA. Credit: The TNG Collaboration

Explore further: Black hole research could aid understanding of how small galaxies evolve

More information: Volker Springel et al. First results from the IllustrisTNG simulations: matter and galaxy clustering, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx3304

Dylan Nelson et al. First results from the IllustrisTNG simulations: the galaxy colour bimodality, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx3040

Annalisa Pillepich et al. First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx3112

The AREPO simulation code www.h-its.org/tap-software-de/arepo-code/

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34 comments

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Benni
1.4 / 5 (11) Feb 01, 2018
How uninteresting.
Whydening Gyre
1.7 / 5 (6) Feb 01, 2018
FTA;
"Like Illustris, the project models a cube-shaped universe smaller than our own"
Shouldn't they try modelling it in a quasi spherical shape?
You know... Realistically?
Hydrodynamics would be COMPLETELY different...
RNP
4.6 / 5 (9) Feb 01, 2018
@Whydening Gyre
FTA;
"Like Illustris, the project models a cube-shaped universe smaller than our own"
Shouldn't they try modelling it in a quasi spherical shape?
You know... Realistically?
Hydrodynamics would be COMPLETELY different...


Actually, the size of the cube is billions of times the scale of any conceivable hydrodynamical process. So, this is not an issue. Besides, to avoid "edge effects" in the model the cube is folded and closed along opposing edges making it "quasi-spherical".
PoppaJ
5 / 5 (3) Feb 01, 2018
I love this! All videos saved for screen saver sequence.
Jaeherys
4.5 / 5 (2) Feb 01, 2018
I thought that the flashes of light from the 3rd video (and the high temperatures they represent) were caused by super novae because it appears to have massive shock waves that spread material throughout galaxy clusters. I don't see that in the IllustrusTNG comparison. Does anyone know what those flashes actually represent and why they don't seem to be present in TNG?
cantdrive85
1.4 / 5 (11) Feb 01, 2018
The most advanced model of GIGO ever produced, as Benni says, how uninteresting and utterly useless.
IMP-9
3.7 / 5 (6) Feb 01, 2018
Does anyone know what those flashes actually represent and why they don't seem to be present in TNG?


They're the effect of the supermassive black holes in the simulation, doing something called AGN Feedback. The physical idea is that accretion SMHBs will generate jets and outflows which will interact with the galaxy and halo, suppressing further star formation. If I recall correctly original Illustris had a rather complicated AGN model where they had two modes, quasar and radio. The biggest black holes in the simulation could move to the higher level, releasing huge amounts of energy in these episodes. AGN feedback is believed to be the mechanism which stops the very biggest galaxies from getting much bigger. In IllustrisTNG I think they ditched the two modes as these bubbles screwed up the galaxies to some extent. It's now a simpler model.
IMP-9
4.7 / 5 (14) Feb 01, 2018
The most advanced model of GIGO ever produced, as Benni says, how uninteresting and utterly useless.


Lol. A simulation which produces realistic looking galaxies, from simple initial conditions taken from the CMB, which has been compared to dozens of observations from all ends of galaxy evolution. Not only that but producing those galaxies with realistic clustering, and large scale structure. Apparently "uninteresting rubbish".

A few snapshots of a basic simulation done decades ago which vaguely look like galaxies, although contain no stars or neutral gas and are simulated isolation. No quantitative comparisons to observations at all. Apparently Nobel worth work as you EU acolytes never shut up about it.

You have no interest in science. Putting models to the test by simulating them objectively and numerically comparing them to observations, that is science. Professing divine truth on youtube is not, the electric universe is pseudoscience.
cantdrive85
1.7 / 5 (11) Feb 01, 2018
A simulation which produces realistic looking galaxies

After years of tweaking, using imaginary objects/matter, and by putting the DM in all the right places to get the desired results. It's little more than computer games, certainly not science. First and foremost, the filamentary/cellular structure of the Universe was not predicted by the standard model nor was the filamentary nature readily accepted initially due to that fact.
It should be noted Alfvén predicted the filamentary/cellular structure way back in 1942 or something, about 50 years before he was proven correct. He relied on the known EM propeties of plasmas to arrive at this prediction, no imaginary DM or physics defying BH's required. But I have no interest in science. What a joke!
cantdrive85
1.5 / 5 (8) Feb 01, 2018
A few snapshots of a basic simulation done decades ago which vaguely look like galaxies,

He did those simulations in his spare time when the Los Alamos supercomputer was not in use and was not able to involve the equivalent amount resources as the plasma ignoramuses did. And as usual, you misrepresent the reality with your lies.
http://plasmauniv...PS-I.pdf
http://plasmauniv...S-II.pdf
Hyperfuzzy
1.7 / 5 (3) Feb 01, 2018
Nice pics, but all this is the product of the wrinkles in Field's of an infinite set of diametrical fields, nothing more.

There's even more up close, where time an space are constrained.
IMP-9
4.6 / 5 (9) Feb 02, 2018
putting the DM in all the right places to get the desired results.


Wrong. The dark matter is seeded with the same initial conditions as the matter, a Gaussian field with a power spectrum from the CMB. The dark matter merely follows the laws of gravity after that point. Peratt's inital conditions however are put in by hand.

the filamentary/cellular structure of the Universe was not predicted by the standard model


Zel'dovich and others did early work showing gravitational collapse forms pancakes, many pancakes makes a cell like structure. What about other predictions? Did Plasma cosmology predict baryon acoustic oscillations (detected in 2005)? No. Did it predict the divergence of galaxy clustering from a single power law (detected 2003)? No. Did it predict the power spectrum of the CMB, perhaps the most striking prediction of standard cosmology? No. Predictions of standard cosmology along with many more. Plamsa cosmology hasn't even explained these things.
IMP-9
4.6 / 5 (9) Feb 02, 2018
But I have no interest in science.


You don't, that's why you constantly reference the same prediction as justification for you and the rest of the EU cult inventing whatever nonsense you like. The point about science is that you test your ideas constantly. Alfven predicting the cosmic web does not confirm his cosmology, and yet your movement have accepted it as biblical scripture. On the other hand standard cosmology has made many confirmed predictions but here you see another simulation, putting it to the test. It's not enough to get one right and conclude cosmology is solved. Observational science has moved so far science "1942", for example the SZ effect has been confirmed which debunks Alfven's claim that the CMB is Galactic. Can Alfven's cosmology match up to the vast observational data available today? Dunno because the EU crowd would rather make videos than scientific simulations to actually test their claims.
cantdrive85
1.5 / 5 (8) Feb 02, 2018
Wrong. The dark matter is seeded with the same initial conditions as the matter,

And then there is the actual observation which debunks DM and simunot to mention the numerous studies out in the past several years which cannot find your magical faerie dust.
Did it predict the power spectrum of the CMB,

The CMB nor your other examples pose any problems for PC whatsoever.
for you and the rest of the EU cult inventing whatever nonsense you like.

Oh, you mean like DM and BH's? Wait, those conjectures were from the plasma ignoramuses postulated way back before the space age, before in situ measurements proved space plasmas behave much like Alfvén predicted.
cantdrive85
1.5 / 5 (8) Feb 02, 2018
And then there is the actual observation which debunks DM

Forgot to include link;
https://phys.org/...mon.html
IMP-9
4.6 / 5 (10) Feb 02, 2018
The CMB nor your other examples pose any problems for PC whatsoever


That's nothing more than an empty claim. No one has ever attempted to explain the CMB power spectrum in plasma cosmology.

Oh, you mean like DM and BH's?


No, and you've made that point for me by posting the link to the dark matter study. What you've proven is that people are testing these ideas. They are attempting to study it observationally and theoretically, people are searching for the cracks. That is science, putting forward a hypothesis and testing it. You may reject dark matter on the basis of dogmatic beliefs, but the way of science is to disprove a hypothesis on the basis of evidence. People built LIGO, they detected the signatures predicted from black hole mergers. And people study the distribution of satellites to test cosmology and galaxy evolution. I don't reject the electric unvierse because of some personal belief, I reject it because you don't test your claims. It's not science.
RNP
4.5 / 5 (8) Feb 02, 2018
@IMP-9
What you've proven is that people are testing these ideas............... I don't reject the electric unvierse because of some personal belief, I reject it because you don't test your claims. It's not science.


Extremely well said. Bravo!

cantdrive85
1.5 / 5 (8) Feb 02, 2018
No one has ever attempted to explain the CMB power spectrum in plasma cosmology.

An empty lie, but what's new...
I don't reject the electric unvierse because of some personal belief, I reject it because you don't test your claims.

It's so sciencey of you to reject proposals that haven't been fully and completely vetted, while at the same time dogishly protecting your own viewpoint. I wonder why the standard theory wasn't presented as a complete and fully vetted TOE as you expect the EU to be.
thingumbobesquire
not rated yet Feb 03, 2018
This is an advanced model of the material physical universe. Yet the mental universe is infinitely (transfinitely) more powerful. It's model is the entirety of nonlinear creative thought's potential to create and harness entirely new states of matter.
IMP-9
4.6 / 5 (9) Feb 03, 2018
An empty lie


It's not a lie, you're just confused. Lerner tried to fit the CMB spectrum, the power spectrum is not the same thing. The specturm is the intensity as a function of wavelength, the power spectrum describes correlation between different points on the sky. Not the same thing. If you think otherwise then provide a source.
IMP-9
4.5 / 5 (8) Feb 03, 2018
It's so sciencey of you to reject proposals that haven't been fully and completely vetted


It's not that you people just haven't got around to it yet, it's that you have no interest in actually testing it. The claims of the electric universe grow by the day as new videos are made about nebulae and galaxies, but these are not presented as speculation. But there is no parallel effort to test these claims quantitatively against the vast astronomical data archives. Lerner on the other hand has attempted to test his ideas, and I have his recent paper. I didn't reject his work on principle, I read it and came to a conclusion about it. If the electric universe start objectively testing their ideas I will be interested, until then it remains pseudoscience.
Benni
1 / 5 (8) Feb 03, 2018
If the electric universe start objectively testing their ideas I will be interested, until then it remains pseudoscience.


......and just take this logic & apply it to Dark Matter research & the pushback is voluminous, especially so since the existence of electricity is settled science.

By contrast, the existence of your vaunted Cosmic Fairy Dust is so far out of whack with the reality of modern detection methodology that it's impossible to make a scientific comparison, "until then it remains pseudoscience", and don't start regurgitating the "inferred gravity" nonsense until you first look up the word "inferred" in the dictionary & discover it's definition.
cantdrive85
1.3 / 5 (9) Feb 03, 2018
It's not that you people just haven't got around to it yet, it's that you have no interest in actually testing it.

Another in a long line of patently false lies, but this is expected from religious types protecting their belief system.
First and foremost, Plasma Cosmology and the Electric Universe concepts are fundamentally and primarily based upon known electrical engineering concepts and laboratory experiments going way back to Maxwell, Birkeland, and Langmuir. These concepts have been laboratory tested since the beginning in direct opposition with the "thought experiments" of Eisteinism.
And to ultimately show your claims are in fact utter lies, one only needs to point to the Safire Project in which the electric sun and electric comet (among other concepts) hypotheses are being tested as we discuss.
http://www.safireproject.com
cantdrive85
1 / 5 (7) Feb 03, 2018
More evidence which shows gimp to be an utter liar.

https://www.resea...nd_Earth
IMP-9
5 / 5 (9) Feb 03, 2018
one only needs to point to the Safire Project


If Safire is really testing the electric sun then what results specifically will rule out the electric sun hypothesis? This is not mentioned on the website. Not all experiments are testing models. You're only really testing a model if there are objective predictions from that model, and therefore you can define what deviations from that model would look like.
Hyperfuzzy
1 / 5 (1) Feb 03, 2018
Nice pics, but all this is the product of the wrinkles in Field's of an infinite set of diametrical fields, nothing more.

There's even more up close, where time an space are constrained.

As we continue to ignore the obvious.
jonesdave
5 / 5 (5) Feb 04, 2018
More evidence which shows gimp to be an utter liar.

https://www.resea...nd_Earth


Non-peer reviewed bobbins.
jonesdave
5 / 5 (4) Feb 04, 2018
......Safire Project in which the electric sun and electric comet (among other concepts) hypotheses are being tested as we discuss.


I'll do you all a favour, and maybe save you some money; don't bother, both of those concepts have already been shown to be nonsense, and are thoroughly ruled out at very high confidence levels.

jonesdave
5 / 5 (4) Feb 04, 2018
If Safire is really testing the electric sun then what results specifically will rule out the electric sun hypothesis?


The fact that they have to plug it into the mains ought to be one :)

mackita
1.7 / 5 (3) Feb 04, 2018
Some features these LCDM models are still missing, because they illustrate only tiny portion of Universe. According to these accretion based model the appearance of Universe should change with distance - which is not what we observe. We observe way too many mature galaxies (these with many heavy elements in their spectra) even in most distant areas of Universe. They also don't describe well the dark matter features (filaments in particular) which have different origin than Jeans instability. And these models also fail in description of features of galaxies based on merging and accretion. Too bad is, these models are opposed only by Plasma Universe supporters, which are equally bigot and biased like the mainstream.
cantdrive85
1 / 5 (5) Feb 04, 2018
The fact that they have to plug it into the mains ought to be one :)

Birkeland had to plug in his Terella, and he was correct with his auroral model. How could that be?

which are equally bigot and biased like the mainstream.

You're right Zephir, we hold pseudoscientist Laviolette in a similar regard to the other great pseudoscientists such as Eddington and Einstein.
savvys84
not rated yet Feb 05, 2018
' sudden evolutionary shift ' how absurd.
Nothing is sudden in this universe including the big bang
Hyperfuzzy
not rated yet Feb 05, 2018
Nice pics, but all this is the product of the wrinkles in Field's of an infinite set of diametrical fields, nothing more.

There's even more up close, where time an space are constrained.

Didn't this explain everything? I think so, find a flaw!
mackita
not rated yet Feb 22, 2018
The results of the computer simulations are problem-ridden, and have been since the very first ones. The clumping matter, it turns out, creates too many small "dwarf" galaxies. Also, the distribution of dark matter inside the galaxies is too peaked towards the middle, a trouble known as the "cusp problem." The simulations also leave some observations unexplained, such as an empirically well-established relation between the brightness of a galaxy and the velocity of its outermost stars, known as the Tully-Fisher-relation.

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