Galaxies feed on tremendous, twisted filaments of gas akin to swirly straws, according to new computer simulations. Gas twists as it falls into falls into galaxies, forming the material for new star formation. As the hydrogen and helium continues to sink into center of the great stellar formations, new stars are born, helping to grow the galaxy.
Researchers used supercomputers at JPL, the University of Irvine and Ames Research Center to run a series of four simulations re-creating the formation of galaxies much like the Milky Way. The simulations began by modeling the hydrogen, helium and dark matter known to exist in the early Cosmos and running the simulation through what would occur through the action of the known laws of physics. The results showed that such stellar groupings would feed through giant filaments of gas like a swirly straw.
"Galaxy formation is really chaotic," Kyle Stewart, lead author of the paper announcing the results, said. "It took us several hundred computer processors, over months of time, to simulate and learn more about how this process works."
Stewart is currently employed by California Baptist University, but conducted most of this new research while at Jet Propulsion Laboratory.
It was a commonly-held theory among astronomers and cosmologists that gas fell into a galaxy from all sides in order to fed the birth of new stars. The ideas held that these gas clouds fell into galaxies, and as they collided with one another, would heat the material around them, triggering the process of star formation. Over the course of up to eight billion years, went the theory, this heated gas would cool as it fell in toward the center of a galaxy. This new "cold-mode" process of galactic growth could take place over just one billion years.
Supercomputers were required for the study due to the tens of millions of particles being tracked while running the program.
"The simulations are like a gigantic game of chess," Alyson Brooks, of the University of Wisconsin and co-author of the paper said. "For each point in time, we have to figure out how a given particle - our chess piece - should move based on the positions of all of the other particles... so figuring out how the gravitational forces affect each particle is time-consuming."
Some galaxies show large, rapidly-rotating rings of gas extending far from their galactic centers. The earlier hot-mode model of galaxy formation could not explain this behavior, but the newer model allows for such action.
Galaxies are believed to have formed in the early Universe from regions where material was denser than the surrounding medium. These protogalaxies were connected to each other by lengthy filaments of gas.
Results of the simulation appear in the May 20 issue of the Astrophysical Journal.
