Cosmologists create record-breaking simulation of galaxy formation

Cosmologists create largest simulation of galaxy formation, break their own record
Composite which combines gas temperature (as the color) and shock mach number (as the brightness). Red indicates 10 million Kelvin gas at the centers of massive galaxy clusters, while bright structures show diffuse gas from the intergalactic medium shock heating at the boundary between cosmic voids and filaments. Credit: Illustris Team

By understanding the stars and their origins, we learn more about where we come from. However, the vastness of the galaxy—let alone the entire universe—means experiments to understand its origins are expensive, difficult and time consuming. In fact, experiments are impossible for studying certain aspects of astrophysics, meaning that in order to gain greater insight into how galaxies formed, researchers rely on supercomputing.

In an attempt to develop a more complete picture of , researchers from the Heidelberg Institute for Theoretical Studies, the Max-Planck Institutes for Astrophysics and for Astronomy, the Massachusetts Institute of Technology, Harvard University, and the Center for Computational Astrophysics in New York have turned to supercomputing resources at the High-Performance Computing Center Stuttgart (HLRS), one of the three world-class German supercomputing facilities that comprise the Gauss Centre for Supercomputing (GCS). The resulting simulation will help to verify and expand on existing experimental knowledge about the universe's early stages.

Recently, the team expanded on its 2015 record-breaking "Illustris" simulation—the largest-ever hydrological simulation of galaxy formation. Hydrodynamic simulations allow researchers to accurately simulate the movement of gas. Stars form from cosmic gas, and starlight provides astrophysicists and cosmologists with important information for understanding how the universe works.

The researchers improved on the scope and accuracy of their simulation, naming this phase of the project Illustris: The Next Generation (IllustrisTNG). The team released its first round of findings across three journal articles appearing in the Monthly Notices of the Royal Astronomical Society and are preparing several more for publication.

Magnetic modelling

Just as humanity cannot envision exactly how the universe came to be, a computer simulation cannot recreate the birth of the universe in a literal sense. Instead, researchers feed equations and other starting conditions—observations from satellite arrays and other sources—into a gigantic computational cube representing a large swath of the universe and then use numerical methods to set in motion this "universe in a box."

For many aspects of the simulation, researchers can start their calculations at a fundamental, or ab initio, level with no need for preconceived input data, but processes that are less understood—such as and the growth of supermassive black holes—need to be informed by observation and by making assumptions that can simplify the deluge of calculations.

Cosmologists create largest simulation of galaxy formation, break their own record
Gas density (left) and magnetic field strength (right) centered on the most massive galaxy cluster. Zoomed panels show the magnetic field orientation and stellar light (top) and xray and radio emission from massive cluster (bottom). Credit: Illustris Team

As computational power and know-how have increased, so, too, has the ability to simulate larger areas of space and increasingly intricate and complex phenomena related to galaxy formation. With IllustrisTNG, the team simulated three universe "slices" at different resolutions. The largest was 300 megaparsecs across, or roughly 1 billion light years. The team used 24,000 cores on Hazel Hen over the span of 35 million core hours.

In one of IllustrisTNG 's major advances, the researchers reworked the simulation to include a more precise accounting for magnetic fields, improving the simulation's accuracy. "Magnetic fields are interesting for a variety of reasons," said Prof. Dr. Volker Springel, professor and researcher at the Heidelberg Institute for Theoretical Studies and principal investigator on the project. "The magnetic pressure exerted on cosmic gas can occasionally be equal to thermal (temperature) pressure, meaning that if you neglect this, you will miss these effects and ultimately compromise your results."

While developing IllustrisTNG the team also made a surprising advance in understanding black hole physics. Based on observational knowledge, the researchers knew that propel cosmic gases with a lot of energy while also "blowing" this gas away from galaxy clusters. This helps to "shut off" star formation in the biggest galaxies and thus imposes a limit on the maximum size they can reach.

In the previous Illustris simulation, the researchers noticed that while black holes go through this energy transfer process, they would not shut off the star formation completely. By revising the ' physics in the simulation, the team saw much better agreement between the data and observation, giving researchers greater confidence that their simulation corresponds to reality.

A long-standing alliance

The team has been using GCS resources since 2015 and been running the IllustrisTNG simulation on HLRS resources since March 2016. Considering that IllustrisTNG's dataset is both larger and more accurate than the original, the researchers are confident their data will be widely used while they apply for more time to continue refining the simulation. The original Illustris data release garnered 2,000 registered users and resulted in more than 130 publications.

During that time, the have relied on GCS support staff to help with several low-level issues related to their code, specifically related to memory crashes and file system issues. Team members Drs. Dylan Nelson and Rainer Weinberger also both benefited from attending 2016 and 2017 machine-level scaling workshops at HLRS. The team's long-standing collaboration with HLRS has resulted in winning 2016 and 2017 Golden Spike awards, which are given to outstanding user projects during HLRS' annual Results and Review Workshop.

Nelson pointed out that while current-generation supercomputers have enabled simulations that have largely overcome most fundamental issues related to massive-scale cosmological modelling, there are still opportunities for improvement.

"Increased memory and processing resources in next-generation systems will allow us to simulate large volumes of the universe with higher resolution," Nelson said. "Large volumes are important for cosmology, understanding the large-scale structure of the universe, and making firm predictions for the next generation of large observational projects. High resolution is important for improving our physical models of the processes going on inside of individual galaxies in our ."


Explore further

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

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
Provided by Gauss Centre for Supercomputing
Citation: Cosmologists create record-breaking simulation of galaxy formation (2018, March 20) retrieved 22 September 2019 from https://phys.org/news/2018-03-cosmologists-record-breaking-simulation-galaxy-formation.html
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Mar 20, 2018
By understanding the stars and their origins, we learn more about where we come from.

Yes, well of course this is so if you do not accept the plain and straight-forward message of our origins contained in Genesis 1.
Now you are entangled in a complex web of IFs and PERHAPSs which all defy real-life observations and simple physics and chemistry 101.

Stars that form by themselves from clouds of gas, planets that form all by themselves from clouds of dust. Living cells, multi-cellular organisms and eventually unimaginably complex human beings that all jump up spontaneously from the random action of chemical and physical processes - all by themselves with no outside intelligent agent required, no matter how irrational it all appears.

All the simulation on the most sophisticated computers using the most complex software is just so much chaff when the assumptions are invalid. There is no way to verify the output - no one can re-create the universe unless they are gods.

Mar 20, 2018
"Magnetic fields are interesting for a variety of reasons," said Prof. Dr. Volker Springel, professor and researcher at the Heidelberg Institute for Theoretical Studies and principal investigator on the project. "The magnetic pressure exerted on cosmic gas can occasionally be equal to thermal (temperature) pressure

What he is neglecting to mention is that magnetic fields oppose star and galaxy self-formation and is therefore a significant obstacle in the actual working of the current nebular theory.

Mar 20, 2018
Yes, well of course this is so if you do not accept the plain and straight-forward message of our origins contained in Genesis 1.


I know Occam's Razor is a thing, but that is referring to a different kind of simplicity. Any reasonable person will reject the delusions noted down in a book 2,000 years ago where the "plain and straight forward" explanation of how the universe originated is some bored super cosmic entity snapping his/her metaphorical fingers (metaphorical since it doesn't have any prior to the creation of the stuff that took billions of years to form the thing we now call 'finger') in order to create TRILLIONS of planets just to put beings kind of similar to him on one of those planets... and then kick them out of a non physical plane called paradise (which wasn't on the actual Earth he created?) just because Eve ate an apple.

TBC

Mar 20, 2018
cont'd

Stars that form by themselves from clouds of gas, planets that form all by themselves from clouds of dust. .


If by 'by themselves' you mean through underlying forces which we have been able to ascertain and define quite well over the past centuries, then sure.

[...] random action of chemical and physical processes - all by themselves with no outside intelligent agent required, no matter how irrational it all appears


So you're telling me that it is more rational to you that complex beings came into existence at an instant, rather than the process we KNOW is responsible, whereby incremental changes/improvements in fitness occurred over ONE BILLION years? I don't know if you're from the future and it's April 1st where you are, or you're from the dark ages but I refuse to believe that you fail to see the irony in you saying that the bible's origin story is more rational than our current theories. Really makes me wonder why you're on this site.

Mar 20, 2018
"Magnetic fields are interesting for a variety of reasons," said Prof. Dr. Volker Springel, professor and researcher at the Heidelberg Institute for Theoretical Studies and principal investigator on the project. "The magnetic pressure exerted on cosmic gas can occasionally be equal to thermal (temperature) pressure, meaning that if you neglect this, you will miss these effects and ultimately compromise your results."

So basically all previous attempts to model the Universe w/o explicitly considering magnetic fields are GIGO.
As a side note, any attempt to model said Universe w/o considering the electric currents/fields which create the magnetic fields is also GIGO. In conclusion, the above model is a record breaking display of GIGO!

Mar 20, 2018
So basically all previous attempts to model the Universe w/o explicitly considering magnetic fields are GIGO.
As a side note, any attempt to model said Universe w/o considering the electric currents/fields which create the magnetic fields is also GIGO. In conclusion, the above model is a record breaking display of GIGO!


And what the hell would you know? You follow a cult whose leaders believe Earth used to orbit Saturn in the recent past. And that Venus was doing handbrake turns around the solar system equally recently. Sorry, but if you believe rubbish like that, then you have no more reason to be posting on this site than religious loons like Fred.


Mar 20, 2018
jonesdumb, using his new branch of physics called General Magnetivity, has proposed that the magnetic fields are magically there. He truly believes the fields are frozen-in to the plasma, as if this plasma is ferromagnetic. ROTFLMAO!

Mar 20, 2018
jonesdumb, using his new branch of physics called General Magnetivity, has proposed that the magnetic fields are magically there. He truly believes the fields are frozen-in to the plasma, as if this plasma is ferromagnetic. ROTFLMAO!


Which fields are frozen-in? Some can be treated as such, some not. Depends on whether the field is high, and the plasma density low, or vice versa. And also for the time period over which it is being studied. Alfven would tell you that. And we've discovered a lot more since he departed the scene. So plasma physicists (of which EU has none) know this very well, and have for some time.
They don't need a bunch of Saturnist, Velikovskian loons telling them their jobs. Not that you are, as you wouldn't go anywhere near the scientific literature with your misconceptions.

Mar 20, 2018
Which fields are frozen-in? Some can be treated as such, some not. Depends on whether the field is high, and the plasma density low, or vice versa.

That is what one calls General Magnetivity, it's the new pseudoscience to pair with the otger great pseudoscience, General Relativity.

Mar 20, 2018
Which fields are frozen-in? Some can be treated as such, some not. Depends on whether the field is high, and the plasma density low, or vice versa.

That is what one calls General Magnetivity, it's the new pseudoscience to pair with the otger great pseudoscience, General Relativity.


You are an idiot. Anyone ever told you that? WHAT IS YOUR POINT, LOONY TUNES?

Mar 22, 2018
The ostrich always hides its head in the sand to avoid inconvenient truths

It is becoming clearer from galactic observations, their orbital star rotation, there is no darkmatter as confirmed by Fritz Zwicky's gravitational observations. Star and galaxy formation are preceding the cosmic background radiation and blackholes are actually light radius stars i.e. they're not a singularity; Because LIGO has confirmed gravity travelling at the speed of so gravity can only compress matter to R=2GM/C*. Theoretical research is no substitute for real practical investigation!

Mar 22, 2018
Proponents of galactic darkmatter

For the proponents of galactic darkmatter increasing the existing matter in galactic formations, the increased gravitation will result in the total collapse of all the Galaxies resulting in an explosion the like that has never been seen before.

Mar 25, 2018
The Universe is actually a Steady State type of being, no need for a beginning, no need for an end. Consider just timescales to size as frame of reference. Things at our Submicroscopic level happens extremely fast, so, if on it's scale it takes, say, an electron a billion years to spin, then compare that to our Galaxies, then we can look at the Outer Cosmological Scale and ask "If our Universe only started 13.8 Billion years ago, then how do we have such fine grained spirals that MUST have taken more than 14 spins for them to attain their size, shape and structure?

How old would the person in a galaxy (that we see as an electron) would they assume their own Universe to be. How Big would it seem to them. How big is ours, really?

I see the polarity seen in the Cosmic Background Radiation seems to show a decompression from an earlier slightly more compressed form. This gives nothing to stop it from having pressure waves that will increase 'local' (what we can observe) densities.

Mar 26, 2018
I know Occam's Razor is a thing, but that is referring to a different kind of simplicity
-And what can be simpler than 'god did it'? Religionists resent complexity almost as much as they resent evidence. Both threaten their control of the situation.

No wonder they worship the ultimate Control Freak.

Mar 26, 2018
The ostrich always hides its head in the sand to avoid inconvenient truths

It is becoming clearer from galactic observations, their orbital star rotation, there is no darkmatter as confirmed by Fritz Zwicky's gravitational observations. Star and galaxy formation are preceding the cosmic background radiation and blackholes are actually light radius stars i.e. they're not a singularity; Because LIGO has confirmed gravity travelling at the speed of [?] so gravity can only compress matter to R=2GM/C*. Theoretical research is no substitute for real practical investigation!


Is the speed of water measured by how fast waves ripple through it?

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