Image: The slumbering giant galaxy at the center of this image is 10 billion light-years away.
Credit: ESA/Hubble & NASA, A. Newman, M. Akhshik, K. Whitaker
“The most massive galaxies in our universe formed incredibly early, just after the Big Bang happened, 14 billion years ago,” says Kate Whitaker, professor of astronomy at UMass Amherst. “But for some reason, they have shut down. They’re no longer forming new stars.” Star formation is one of the key ways that galaxies grow, and they’re said to have gone quiescent when they cease forming stars. Astronomers have known that these early, massive galaxies had gone quiescent, but until now, no one knew why.
To find the answer, Whitaker’s team, which includes Alexandra Pope, professor of astronomy, and Christina C. Williams, who received her Ph.D. in astronomy at UMass, devised an innovative pairing of telescopes. They used the Hubble Space Telescope, which sees ultraviolet to near-infrared light, including the light we can see with our own eyes, to detect these distant galaxies, which are so far away that we’re only just now seeing the light they emitted 10 billion to 12 billion years ago, when the universe was in its infancy. In effect, Whitaker’s team is looking into the deep past.