Distant, dust-filled galaxies were bursting with newborn stars much earlier in cosmic history than previously thought, a new study suggests.
So-called “starburst galaxies” produce stars at the equivalent of a thousand new suns per year.
Now, astronomers have found starbursts that were churning out stars when the universe was just a billion years old.
Joaquin Vieira, a postdoctoral scholar at the California Institute of Technology and leader of the study said that these aren’t normal galaxies.
“These galaxies [reveal star formation] at an extraordinary rate, when the universe was very young. I don’t think anyone expected us to find galaxies like this so early in the history of the universe,” Vieira said.
An international team of astronomers found dozens of these galaxies with the National Science Foundation- (NSF) funded South Pole Telescope (SPT).
SPT is a 10-meter dish in Antarctica that surveys the sky in millimeter-wavelength light, whose waves fall between radio waves and infrared on the electromagnetic spectrum.
The team then took a more detailed look using the new Atacama Large Millimeter Array (ALMA) in Chile’s Atacama Desert, which is funded in part by NSF.
ALMA is an international facility and is a partnership between North America, Europe and East Asia in cooperation with the Republic of Chile.
“The new observations represent some of ALMA’s most significant scientific results yet. We couldn’t have done this without the combination of SPT and ALMA. ALMA is so sensitive, it is going to change our view of the universe in many different ways,” Vieira said.
The research enables astronomers to study the earliest bursts of star formation and to understand how galaxies formed and evolved.
Shining in the infrared with the energy of a trillion suns, these newly discovered starburst galaxies represent what the most massive galaxies in our cosmic neighborhood looked like in their star-making youth.
With ALMA, the astronomers found that more than 30 percent of the new galaxies are from a time period just 1.5 billion years after the Big Bang.
Previously, only nine such galaxies were known to exist, and it wasn’t clear whether galaxies could produce stars at such high rates so early in cosmic history.
Now, with the new discoveries, that number has nearly doubled, providing valuable data that will help other researchers constrain and refine computer models of star and galaxy formation in the early universe.
The findings are published in the journal Nature.