Heavy Metal in the Early Cosmos - Simulation

This simulation shows heavy-element-bearing sheets of an exploding star's debris streaming into the center of a cosmic dark matter halo. 

Upon arriving in the center, the streams will enable the formation of the first low-mass stars, when the universe was still only about 200 million years old. 

Image courtesy Jeremy Ritter, Milos Milosavljevic, and Volker Bromm, The University of Texas at Austin.

Ab initio: "From the beginning." It's a term used in science to describe calculations that rely on established mathematical laws of nature, or "first principles," without additional assumptions or special models.

Milos Milosavljevic

But when it comes to the phenomena that Milos Milosavljevic is interested in calculating, we're talking really ab initio, as in from the beginning of time onward.

Things were different in the early eons of the universe.

The cosmos experienced rapid inflation; electrons and protons floated free from each other; the universe transitioned from complete darkness to light; and enormous stars formed and exploded to start a cascade of events leading to our present-day universe.

Working with Chalence Safranek-Shrader and Volker Bromm at the University of Texas at Austin, Milosavljevic recently reported the results of several massive numerical simulations charting the forces of the universe in its first hundreds of millions of years using some of the world's most powerful supercomputers, including the National Science Foundation (NSF) -supported Stampede, Lonestar and Ranger (now retired) systems at the Texas Advanced Computing Center.

The results, described in the Monthly Notices of the Royal Astronomical Society in January 2014, refine how the first galaxies formed, and in particular, how metals in the stellar nurseries influenced the characteristics of the stars in the first galaxies.

"The universe formed at first with just hydrogen and helium," Milosavljevic said. "But then the very first stars cooked metals and after those stars exploded, the metals were dispersed into ambient space."

This simulation shows hydrodynamic instability triggered by rapid cooling in a heavy-element-enriched cosmic dark matter halo when the universe was only 300 million years old.

The instability drives turbulence which breaks the flow into fragments. 

Some fragments undergo gravitational collapse and set to fragment into progressively smaller units. 

From left to right and top to bottom, the six panels show projections of gas density, and the horizontal bar has length 1 pc = 3.26 light years.

Credit: Chalence Safranek-Shrader, Milos Milosavljevic, and Volker Bromm, the University of Texas at Austin

More Information: 'Heavy metal in the early cosmos' Monthly Notices of the Royal Astronomical Society in January 2014 - Milos Milosavljevic, Chalence Safranek-Shrader and Volker Bromm