UT astronomy professor challenges the current model on dark matter

Radhika Vaishnav

Scientists like to think they know at least some things about the galaxies we live in, but researchers such as Dr. Michael Boylan-Kolchin, an astronomy professor at UT, are changing some of those perspectives.

Earlier in February, a study by astronomy researchers from the University of California, Irvine and the University of Basel in Switzerland discovered that the way satellites, or objects that orbit galaxies, are stationed is inconsistent with 99 percent of galaxies created in simulations. This implies that the current model for the satellites and galaxies is incorrect.

Boylan-Kolchin said this discovery by scientists in Irvine and Switzerland could lead to new perspectives on how we see our universe. The widely-accepted model used to demonstrate the way the universe moves and grows is called the “dark energy plus cold matter” model. However, new research, including some by Boylan-Kolchin, suggests that this model is inaccurate and might need to be revised.

Boylan-Kolchin’s area of research is numerical galaxy formation and dark matter physics. Dark matter is an unexplained mass that affects cosmological structure and how galaxies move.

“I study how we can understand how galaxies form and evolve,” Boylan-Kolchin said. “Instead of using observations directly, I mostly use supercomputers and simulations and then try and use observations to try and tell us whether those simulations are giving us a correct model of the universe.”

Currently, Boylan-Kolchin’s group is running many simulations at the Texas Advanced Computing Center. They do simulations where they attempt to understand the universe on a large scale, meaning they try to simulate many galaxies at the same time in order to get a representative portion of the universe. Another approach his group uses is simulating one galaxy almost perfectly in order to see if they can understand that specific galaxy in detail.

His team also tries to make connections between nearby galaxies and galaxies that formed in the very earliest phases of the universe. Although these galaxies are hard to see because they are so far away, Boylan-Kolchin said his team can actually see what is left over by ancient galaxies by studying what is right next to nearby galaxies.

“One of the interesting things we can do (in a simulation) is keep everything the same, except change a little bit about what we think the nature of dark matter is,” he said. “(We can) see how those changes will affect potential observations.”

Boylan-Kolchin said he hopes that his research on galaxy formation and dark matter physics will change predictions of what happens in galaxies and how they work.

“One of the main parts of my research is rooted in things that have happened before, so we have to know what people have been doing and have the perspective to figure out if what we are doing fits in that,” Boylan-Kolchin said. “A lot of this is driven by trying to improve on what others have done and see the flaws and the areas that they have not covered.”