Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Interstellar mystery solved by supercomputer simulations

12.12.2014

Galaxy evolution modeled on NSF XSEDE Stampede supercomputer of the Texas Advanced Computing Center

An interstellar mystery of why stars form has been solved thanks to the most realistic supercomputer simulations of galaxies yet made.


Spiral structure emerges in Feedback in Realistic Environments (FIRE) simulation, which modeled stellar feedback on galaxy formation.

Theoretical astrophysicist Philip Hopkins of the California Institute of Technology (CalTech) led research that found that stellar activity — like supernova explosions or even just starlight — plays a big part in the formation of other stars and the growth of galaxies.


"The Stampede supercomputer at TACC was the workhorse of these simulations."
Philip Hopkins, assistant professor of theoretical astrophysics, California Institute of Technology.


"Feedback from stars, the collective effects from supernovae, radiation, heating, pushing on gas, and stellar winds can regulate the growth of galaxies and explain why galaxies have turned so little of the available supply of gas that they have into stars," Hopkins said.

Galaxy simulations were tested on the Stampede supercomputer of the Texas Advanced Computing Center (TACC), an Extreme Science and Engineering Discovery Environment-allocated (XSEDE) resource funded by the National Science Foundation.

The initial results were published September of 2014 in the Monthly Notices of the Royal Astronomical Society. Hopkins's work was funded by the National Science Foundation, the Gordon and Betty Moore Foundation, and a NASA Einstein Postdoctoral Fellowship.

The mystery begins in interstellar space, the vast space between stars. There dwell enormous clouds of molecules, mainly hydrogen, with the mass of thousands or even millions of Suns. These molecular gas clouds condense and give birth to stars.

What's puzzled astrophysicists since the 1970s is their observations that only a small fraction of matter in the clouds becomes a star. The best computer simulations, however, predicted nearly all of a cloud's matter would cool and become a star.

"That's really what we were trying to figure out and address, for the first time, by putting in the real physics of what we know stars do to the gas around them," Hopkins said.

A multi-institution collaboration formed with members from CalTech, U.C. Berkeley, U.C. San Diego, U.C. Irvine, Northwestern, and the University of Toronto. They produced a new set of supercomputer galaxy models called FIRE or Feedback in Realistic Environments. It focused the computing power on small scales of just a few light years across.

"We started by simulating just single stars in little patches of the galaxy, where we trace every single explosion," Hopkins explained. "That lets you build a model that you can put into a simulation of a whole galaxy at a time. And then you build that up into simulations of a chunk of the universe at a time."

Hopkins developed the simulation code locally on a cluster at CalTech, but the Stampede supercomputer did the lion's share of the computation.

"Almost all of these simulations were run on XSEDE resources," Hopkins said. "In particular the Stampede supercomputer at TACC was the workhorse of these simulations…Stampede was an ideal machine — it was fast, it had large shared memory nodes with a lot of processors per node and good memory per processor. And that let us run this on a much faster timescale than we had originally anticipated. Combined with improvements we made to the parallelization of the problem, we were able to run this problem on thousands of CPUs at a time, which is record-breaking for this type of problem," Hopkins said.

The realism achieved by the FIRE galaxy simulations surprised Hopkins. Past work with sub-grid models of how supernovae explode and how radiation interacts with gas required manually tweaking the model after each run.

"My real jaw-dropping moment," Hopkins said, "was when we put the physics that we thought had been missing from the previous models in without giving ourselves a bunch of nobs to turn. We ran it and it actually looked like a real galaxy. And it only had a few percent of material that turned into stars, instead of all of it, as in the past."

FIRE has mostly simulated the more typical and small galaxies, and Hopkins wants to build on its success. "We want to explore the odd balls, the galaxies that we see that are of strange sizes or masses or have unusual properties in some other way," Hopkins said.

Hopkins also wants to model galaxies with supermassive black holes at the center, like our own Milky Way. "In the process of falling in, before matter actually gets trapped by the black hole and nothing can escape, it turns out that for the most massive galaxies, this is even more energy than released by all the stars in the galaxy. It's almost certainly important. But it's at the edge, and we're just starting to think about simulating those giant galaxies," Hopkins said.

Jorge Salazar | EurekAlert!

Further reports about: Advanced Computing FIRE Galaxies Technology clouds interstellar supernovae

More articles from Physics and Astronomy:

nachricht Taking a spin on plasma space tornadoes with NASA observations
20.11.2017 | NASA/Goddard Space Flight Center

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Water world

20.11.2017 | Life Sciences

Less is more to produce top-notch 2D materials

20.11.2017 | Materials Sciences

Carefully crafted light pulses control neuron activity

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>