A team of astronomers that included an assistant professor at the University of Massachusetts Amherst has discovered a massive “monster galaxy” 12.5 billion light-years away that was hiding behind a cloud of stardust.
Kate Whitaker, the UMass Amherst professor who was one of the coauthors of a paper on the discovery published Tuesday in the Astrophysical Journal, said it was surprising because it is rare to find a huge galaxy that is so ancient.
The light from the galaxy has taken 12.5 billion years to reach Earth. So that would make what scientists are observing that old, which would place it about 1.2 billion years after the Big Bang, when the universe was still in its infancy.
Whitaker said researchers are intrigued because “the universe was just a baby at this point, and [the newly discovered galaxy] formed 100 times more stars than our Milky Way but billions of years earlier.”
The “monster galaxy” was growing at a very fast rate, but its bright light was hidden from researchers by a cloud of cosmic stardust, a byproduct of star formation, Whitaker said.
The lead author of the paper was Christina Williams, a UMass Amherst alumna who is now a postdoctoral researcher at the University of Arizona.
While looking at data from the Atacama Large Millimeter Array, an observatory in Chile, for an unrelated project, Williams noticed an unmistakable but faint dot of light.
The team compared the light with other data to try to identify it but couldn’t find any trace of the galaxy in existing data.
“It was very mysterious, but the light seemed not to be linked to any known galaxy at all,” Williams said in a statement from UMass Amherst. “When I saw this galaxy was invisible at any other wavelength, I got really excited, because it meant that it was probably really far away and hidden by clouds of dust.”
Justin Spilker, a fellow at the University of Texas at Austin, also worked on the study. He said the discovery opens up the possibility that there are more massive galaxies from the early stages of the universe that have yet to be discovered.
“The fact that we could find one of these things means there’s maybe a lot of them out there,” he said. “The other option is maybe we just got spectacularly lucky. . . . But it’s certainly possible that galaxies like this are sitting in many people’s images.”