Blue Waters Assists Researchers Studying the Early Building Blocks of the Universe

October 26, 2015

Oct. 26 — Why do we care what happened 13 billion years ago?

A bold lead question for an interview with an astrophysicist looking at the early universe, but one that doesn’t seem to faze Brian O’Shea. The Michigan State University professor just smiles across the Skype connection and then chuckles.

“If you are interested in the Milky Way today, then understanding the early universe is really important,” he says, still smiling. “Through a process called hierarchical structure formation, little galaxies form bigger galaxies and bigger and bigger galaxies. It happens over and over again and you get a galaxy like the Milky Way. The main reason I’m interested in these galaxies in the very early universe is that fundamentally they are the progenitors of galaxies like the Milky Way. They are essentially the first building blocks. It’s one of those things where the initial state is really important for what happens at the end.”

O’Shea is no stranger to supercomputing or NCSA, dating back to his days as a student at the University of Illinois at Urbana-Champaign. As leader of a Petascale Computing Resource Allocations (PRAC) team that includes co-principal investigator Michael Norman and Hao Xu at the University of California, San Diego, John Wise of Georgia Tech, and Britton Smith of the University of Edinburgh, O’Shea’s been able to explore early galaxy formation and evolution. The team has published more than 16 papers, primarily in the Astrophysical Journal.

The team’s simulations on Blue Waters are, says O’Shea, the most sophisticated simulations that anyone has ever done of galaxies in the early universe. One of the things they’ve found through the simulations is that early on in the universe there are actually far fewer galaxies than they thought.

“The smaller galaxies are just gone and we don’t completely understand that. Our theory right now is that it is radiation from all of the bigger galaxies that suppresses star formation in the dwarfs,” says O’Shea.

When two galaxies merge with each other to form a larger galaxy it is primarily because the dark matter is drawn together by its gravitational potential, explains O’Shea. Gas is mostly along for the ride in galaxy formation, while stars in a galaxy contribute to, but don’t dominate, pulling together the galaxies. This leads to “dark” halos—matter that’s not seen, doesn’t have much gas in it, and has very few stars or even no stars at all.

“What we’re finding is that some of these dark matter halos have no stars at all. And something else that is really interesting is when you look at the satellite galaxies in the Milky Way the smaller ones are dark matter dominated. In the Milky Way there’s about 10 times as much dark matter as there are stars, and if you look at these really small dwarf galaxies it’s more like 1,000 times more dark matter than there is stars. That’s because it’s really hard to form the stars because of all these other physical effects. And in our simulations where we’re looking at galaxies that are more the size of those dwarf galaxies we see the same thing; that their dark matter clearly dominates. That there’s a hundred times more dark matter than there is stars, or a 1,000 times more dark matter than there is stars.

“So the pieces are actually starting to fall together in terms of understanding what’s going on in these galaxies around the Milky Way. What we’re seeing at high redshift early in the universe when we’re doing these simulations is that the bigger galaxies around are sort of stomping on their buddies. Radiation from the big galaxies keeps the small ones from doing anything exciting, keeps them from forming stars. About a billion years after the Big Bang there’s just enough radiation that the whole universe gets ionized and all of these little galaxies can never form stars after that, they’re just completely quenched for the rest of their lives,” says O’Shea.

What this means, he says, is that there should be a significant number of dark matter halos without any stars in the middle as well as small galaxies with only a few stars that won’t form additional stars. And that actually agrees with the galaxies seen by the Dark Energy Survey (DES) and the Sloan Digital Sky Survey where there’s a hundred more times dark matter than stars, or a thousand times more dark matter than stars in terms of the mass, and all of the star formation happened 13 billion years ago.

“Once you get to stars that are that old the margin of error is a couple billion years, simply because they evolve quite slowly so you can’t quite tell how old they are,” he says with a laugh. “But it’s consistent with this idea of everything happening really early on in the universe.”

Dwarf galaxies around the Milky Way are by and large relics of this first generation of galaxies. O’Shea is excited that analysis of data recorded by the DES has found more dwarf galaxies than previously observed. He says that discovery is the connection between the work his team has been doing on Blue Waters and the galaxy that we live in now.

“The work that we’re doing on Blue Waters is trying to understand how those first galaxies behave. A lot of those galaxies are still around and are still in orbit around the Milky Way, they’re just really hard to find. They’re relics, they’re fossils. The term galactic archaeology refers to looking at all these really old stellar populations, really old galaxies, really old stars, to figure out what was going on in the early universe. These ultra-faint dwarf galaxies that you find in DES are really fossils of what happened in that epoch right after the Big Bang that we are studying directly with our simulations.”

Many Mysteries

Yet for all we learn about the universe there are many, many things in the universe that remain unexplainable, despite decades of galactic research. Take black holes, for instance. There’s a black hole at the center of every massive galaxy, including the Milky Way. Yet no one is quite sure how this region of space forms in which nothing escapes, including light. Nor do researchers know how it grows.

O’Shea and other researchers believe, however, that black holes are “really intimately tied to how galaxies form.” He’s the principal investigator on a recently awarded PRAC allocation that will allow him to connect his work on the early universe to the present day Milky Way. He’ll lead a team that will use Blue Waters to conduct simulations on several aspects of galaxy evolution, including exploring precisely how the early galaxies and black holes turn into present-day galaxies.

Early Stars

Included in the team’s research is star formation. O’Shea is among the researchers who are convinced that early star formation “sets the stage for everything that happens afterwards.” And by sets the stage he means “they produce the metals that pollute the gas that all this star formation occurs in. They change the chemical composition and the actual behavior of the gas; it changes the future generation of star formation.”

The first stars in the universe, called primordial stars, formed during the Big Bang from just hydrogen and helium. Those gases are poor coolants, resulting in hot clouds of gas in the universe. Stars that form from hot gases are significantly larger than stars that form later from cooler gases. The later stars have carbon, nitrogen, oxygen and iron in them, among other things.

“The first generation stars are much bigger and brighter. One of the questions we’ve been trying to answer,” says O’Shea, “is how does that transition take place. We know that at some point there were stars that were primordial and then at some point later there were some stars that have metal. By the way, we call metal anything heavier than helium on the periodic table. That’s a term that astronomers use to mean it came from stars and it absolutely enrages chemists because metal has a very specific meaning in their field. I keep using that word in an indelicate way and I apologize. We’re really interested in the process by which the universe gets polluted with all of this other stuff on the periodic table. So I’m working on a project with Britton Smith and John Wise, and we’re trying to understand how that transition takes place.”

The difference between big stars and small stars is the difference between all of the stars blowing up in supernovae and only some of them blowing up in supernovae, he explains. The size of the stars also affects the radiation emitted.

And the first generation of stars “also probably produce the black holes that end up in the middle of all the galaxies today. We’re not sure about that but it is a plausible theory and some people think it’s true,” says O’Shea.

The mass of a star determines how long it lives. O’Shea says simulations, such as those done by his Michigan State colleague Ed Brown, have shown that smaller stars can live for 20 or 30 billion years, which is longer than the current age of the universe. So many of the smaller, dimmer stars that astronomers observe are most likely “relics of that initial time. But these little stars evolve really slowly. They’re actually offering really useful clues as to what’s going on early in the universe,” he says.

Dense of Void

Another issue O’Shea is exploring is that different parts of the universe are denser than other parts. There are galaxies in groups, like the Milky Way and Andromeda. But there are also voids—large regions that are millions and millions of light years across—that, as far as can be determined, are totally empty.

In his simulations run on Blue Waters, however, instead of being really, really dense or really, really empty these regions are somewhat dense or somewhat empty, but not definitively either dense or empty. Exploring a dense region that would be a galaxy cluster, an average region that the Milky Way would form from, and a low-density region that a void would form from and trying to understand the differences between the over-dense region, the average region and the under-dense region is another research focus O’Shea believes could yield clues about the early universe and its influence on the present day.

“I’m really interested in that, but we’re still in the middle of that analysis,” says O’Shea. “We got sidetracked with other science and there’s not that many of us [on the team]. That’s something that is really interesting because at present day, 13.7 billion years after the Big Bang, it’s really obvious that galaxies behave differently in different environments. So when galaxies are in clusters where they are all packed tightly together and orbiting around each other at hundreds of kilometers a second, galaxies look different in that environment compared to something like the Milky Way. And we want to know where along the line does that actually happen. Do you see differences between environments when you look at galaxies 400 or 500 million years after the Big Bang when the universe is 4 percent of the age that it is today, or does it take longer for those differences to develop? It’s an interesting question, it’s very relevant to modern day galaxy formation. We just haven’t answered it yet.”

Source: Barbara Jewett, NCSA

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

Intel Speeds NAMD by 1.8x: Saves Xeon Processor Users Millions of Compute Hours

August 12, 2020

Potentially saving datacenters millions of CPU node hours, Intel and the University of Illinois at Urbana–Champaign (UIUC) have collaborated to develop AVX-512 optimizations for the NAMD scalable molecular dynamics cod Read more…

By Rob Farber

Intel’s Optane/DAOS Solution Tops Latest IO500

August 11, 2020

Intel’s persistent memory technology, Optane, and its DAOS (Distributed Asynchronous Object Storage) stack continue to impress and gain market traction. Yesterday, Intel reported an Optane and DAOS-based system finishe Read more…

By John Russell

Summit Now Offers Virtual Tours

August 10, 2020

Summit, the second most powerful publicly ranked supercomputer in the world, now has a virtual tour. The tour, implemented by 3D platform Matterport, allows users to virtually “walk” around the massive supercomputer Read more…

By Oliver Peckham

Supercomputer Simulations Examine Changes in Chesapeake Bay

August 8, 2020

The Chesapeake Bay, the largest estuary in the continental United States, weaves its way south from Maryland, collecting waters from West Virginia, Delaware, DC, Pennsylvania and New York along the way. Like many major e Read more…

By Oliver Peckham

Student Success from ‘Scratch’: CHPC’s Proof is in the Pudding

August 7, 2020

Happy Sithole, who directs the South African Centre for High Performance Computing (SA-CHPC), called the 13th annual CHPC National conference to order on December 1, 2019, at the Birchwood Conference Centre in Kempton Pa Read more…

By Elizabeth Leake

AWS Solution Channel

University of Adelaide Provides Seamless Bioinformatics Training Using AWS

The University of Adelaide, established in South Australia in 1874, maintains a rich history of scientific innovation. For more than 140 years, the institution and its researchers have had an impact all over the world—making vital contributions to the invention of X-ray crystallography, insulin, penicillin, and the Olympic torch. Read more…

Intel® HPC + AI Pavilion

Supercomputing the Pandemic: Scientific Community Tackles COVID-19 from Multiple Perspectives

Since their inception, supercomputers have taken on the biggest, most complex, and most data-intensive computing challenges—from confirming Einstein’s theories about gravitational waves to predicting the impacts of climate change. Read more…

New GE Simulations on Summit to Advance Offshore Wind Power

August 6, 2020

The wind energy sector is a frequent user of high-power simulations, with researchers aiming to optimize wind flows and energy production from the massive turbines. Now, researchers at GE are preparing to undertake a lar Read more…

By Oliver Peckham

Intel’s Optane/DAOS Solution Tops Latest IO500

August 11, 2020

Intel’s persistent memory technology, Optane, and its DAOS (Distributed Asynchronous Object Storage) stack continue to impress and gain market traction. Yeste Read more…

By John Russell

Summit Now Offers Virtual Tours

August 10, 2020

Summit, the second most powerful publicly ranked supercomputer in the world, now has a virtual tour. The tour, implemented by 3D platform Matterport, allows use Read more…

By Oliver Peckham

Research: A Survey of Numerical Methods Utilizing Mixed Precision Arithmetic

August 5, 2020

Within the past years, hardware vendors have started designing low precision special function units in response to the demand of the machine learning community Read more…

By Hartwig Anzt and Jack Dongarra

Implement Photonic Tensor Cores for Machine Learning?

August 5, 2020

Researchers from George Washington University have reported an approach for building photonic tensor cores that leverages phase change photonic memory to implem Read more…

By John Russell

HPE Keeps Cray Brand Promise, Reveals HPE Cray Supercomputing Line

August 4, 2020

The HPC community, ever-affectionate toward Cray and its eponymous founder, can breathe a (virtual) sigh of relief. The Cray brand will live on, encompassing th Read more…

By Tiffany Trader

Machines, Connections, Data, and Especially People: OAC Acting Director Amy Friedlander Charts Office’s Blueprint for Innovation

August 3, 2020

The path to innovation in cyberinfrastructure (CI) will require continued focus on building HPC systems and secure connections between them, in addition to the Read more…

By Ken Chiacchia, Pittsburgh Supercomputing Center/XSEDE

Nvidia Said to Be Close on Arm Deal

August 3, 2020

GPU leader Nvidia Corp. is in talks to buy U.K. chip designer Arm from parent company Softbank, according to several reports over the weekend. If consummated Read more…

By George Leopold

Intel’s 7nm Slip Raises Questions About Ponte Vecchio GPU, Aurora Supercomputer

July 30, 2020

During its second-quarter earnings call, Intel announced a one-year delay of its 7nm process technology, which it says it will create an approximate six-month shift for its CPU product timing relative to prior expectations. The primary issue is a defect mode in the 7nm process that resulted in yield degradation... Read more…

By Tiffany Trader

Supercomputer Modeling Tests How COVID-19 Spreads in Grocery Stores

April 8, 2020

In the COVID-19 era, many people are treating simple activities like getting gas or groceries with caution as they try to heed social distancing mandates and protect their own health. Still, significant uncertainty surrounds the relative risk of different activities, and conflicting information is prevalent. A team of Finnish researchers set out to address some of these uncertainties by... Read more…

By Oliver Peckham

Supercomputer-Powered Research Uncovers Signs of ‘Bradykinin Storm’ That May Explain COVID-19 Symptoms

July 28, 2020

Doctors and medical researchers have struggled to pinpoint – let alone explain – the deluge of symptoms induced by COVID-19 infections in patients, and what Read more…

By Oliver Peckham

Nvidia Said to Be Close on Arm Deal

August 3, 2020

GPU leader Nvidia Corp. is in talks to buy U.K. chip designer Arm from parent company Softbank, according to several reports over the weekend. If consummated Read more…

By George Leopold

Intel’s 7nm Slip Raises Questions About Ponte Vecchio GPU, Aurora Supercomputer

July 30, 2020

During its second-quarter earnings call, Intel announced a one-year delay of its 7nm process technology, which it says it will create an approximate six-month shift for its CPU product timing relative to prior expectations. The primary issue is a defect mode in the 7nm process that resulted in yield degradation... Read more…

By Tiffany Trader

Supercomputer Simulations Reveal the Fate of the Neanderthals

May 25, 2020

For hundreds of thousands of years, neanderthals roamed the planet, eventually (almost 50,000 years ago) giving way to homo sapiens, which quickly became the do Read more…

By Oliver Peckham

10nm, 7nm, 5nm…. Should the Chip Nanometer Metric Be Replaced?

June 1, 2020

The biggest cool factor in server chips is the nanometer. AMD beating Intel to a CPU built on a 7nm process node* – with 5nm and 3nm on the way – has been i Read more…

By Doug Black

HPE Keeps Cray Brand Promise, Reveals HPE Cray Supercomputing Line

August 4, 2020

The HPC community, ever-affectionate toward Cray and its eponymous founder, can breathe a (virtual) sigh of relief. The Cray brand will live on, encompassing th Read more…

By Tiffany Trader

Neocortex Will Be First-of-Its-Kind 800,000-Core AI Supercomputer

June 9, 2020

Pittsburgh Supercomputing Center (PSC - a joint research organization of Carnegie Mellon University and the University of Pittsburgh) has won a $5 million award Read more…

By Tiffany Trader

Leading Solution Providers

Contributors

Nvidia’s Ampere A100 GPU: Up to 2.5X the HPC, 20X the AI

May 14, 2020

Nvidia's first Ampere-based graphics card, the A100 GPU, packs a whopping 54 billion transistors on 826mm2 of silicon, making it the world's largest seven-nanom Read more…

By Tiffany Trader

Australian Researchers Break All-Time Internet Speed Record

May 26, 2020

If you’ve been stuck at home for the last few months, you’ve probably become more attuned to the quality (or lack thereof) of your internet connection. Even Read more…

By Oliver Peckham

15 Slides on Programming Aurora and Exascale Systems

May 7, 2020

Sometime in 2021, Aurora, the first planned U.S. exascale system, is scheduled to be fired up at Argonne National Laboratory. Cray (now HPE) and Intel are the k Read more…

By John Russell

‘Billion Molecules Against COVID-19’ Challenge to Launch with Massive Supercomputing Support

April 22, 2020

Around the world, supercomputing centers have spun up and opened their doors for COVID-19 research in what may be the most unified supercomputing effort in hist Read more…

By Oliver Peckham

Joliot-Curie Supercomputer Used to Build First Full, High-Fidelity Aircraft Engine Simulation

July 14, 2020

When industrial designers plan the design of a new element of a vehicle’s propulsion or exterior, they typically use fluid dynamics to optimize airflow and in Read more…

By Oliver Peckham

John Martinis Reportedly Leaves Google Quantum Effort

April 21, 2020

John Martinis, who led Google’s quantum computing effort since establishing its quantum hardware group in 2014, has left Google after being moved into an advi Read more…

By John Russell

$100B Plan Submitted for Massive Remake and Expansion of NSF

May 27, 2020

Legislation to reshape, expand - and rename - the National Science Foundation has been submitted in both the U.S. House and Senate. The proposal, which seems to Read more…

By John Russell

Google Cloud Debuts 16-GPU Ampere A100 Instances

July 7, 2020

On the heels of the Nvidia’s Ampere A100 GPU launch in May, Google Cloud is announcing alpha availability of the A100 “Accelerator Optimized” VM A2 instance family on Google Compute Engine. The instances are powered by the HGX A100 16-GPU platform, which combines two HGX A100 8-GPU baseboards using... Read more…

By Tiffany Trader

  • arrow
  • Click Here for More Headlines
  • arrow
Do NOT follow this link or you will be banned from the site!
Share This