New research looks at how ‘cosmic web’ of filaments alters star formation in galaxies

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LAWRENCE — Astronomer Gregory Rudnick sees the universe crisscrossed by something like an interstellar superhighway system. Filaments — the strands of aggregated matter that stretch millions of light years across the universe to connect galaxy clusters — are the freeways.

“Galaxies will flow along filaments from less dense parts of the universe to more dense parts of the universe, kind of like cars flowing down a highway to the big city. In this case, they are going toward big clusters, being pulled by the gravity of those large concentrations of matter,” he said.

Rudnick, associate professor of physics & astronomy at the University of Kansas, wants to know more about how filaments influence galaxies that are moving through them. Now, the KU researcher has earned a $280,000 grant from the National Science Foundation to lead an international collaboration that is investigating galaxies that extend along this “cosmic web” of filaments.

“I’m interested in how galaxies are affected by the regions in which they live,” Rudnick said. “Filaments are the first place where galaxies come into contact with higher density regions of the universe. If a galaxy in a ‘rural’ part of the universe enters a dense part, I want to know how its properties change — for example, does it change the number of stars it forms, or does its shape get altered? Using the highway analogy, when you drive into Kansas City, as you go there are more and more cars building up next to you, and sometimes there are car accidents — this is something like the real universe because galaxies can collide, too.”

Rudnick and colleagues will use multiple telescopes around the world to observe neutral hydrogen and molecular gas in galaxies as they travel along filaments. The team hopes to determine if the amount of gas — the fuel for star formation — is less abundant in filament galaxies than in galaxies from other …

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