In what James Webb Space Telescope researchers call a “whole new chapter in astronomy,” the observatory has helped to locate two early galaxies, one of which may contain the most distant starlight ever seen.
In a tweet, the international team said the unexpectedly bright galaxies could fundamentally alter what is known about the very first stars.
The research – two papers – was published last week in the Astrophysical Journal Letters.
With just four days of analysis, researchers found the galaxies in the images from the Grism Lens-Amplified Survey from Space (GLASS) Early Release Science (ERS) program.
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The scientists found that the galaxies existed around 450 and 350 million years after the big bang, though future spectroscopic measurements with Webb will help confirm these initial findings.
“With Webb, we were amazed to find the most distant starlight that anyone had ever seen, just days after Webb released its first data,” Rohan Naidu, of the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology, told NASA of the more distant GLASS galaxy – referred to as GLASS-z12 – which is believed to date back to 350 million years after the big bang.
Naidu led one paper and Marco Castellano, of the National Institute for Astrophysics in Rome, Italy, led the other.
The previous record holder is galaxy GN-z11, which existed 400 million years after the big bang.
“While the distances of these early sources still need to be confirmed with spectroscopy, their extreme brightnesses are a real puzzle, challenging our understanding of galaxy formation,” the University of Geneva’s Pascal Oesch said.
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The observations reportedly push astronomers toward a consensus that an unusual number of galaxies in the early universe were much brighter than expected, making it easier for the telescope to find even more early galaxies.
“We’ve nailed something that is incredibly fascinating. These galaxies would have had to have started coming together maybe just 100 million years after the Big Bang. Nobody expected that the dark ages would have ended so early,” said Garth Illingworth of the University of California at Santa Cruz, a member of the Naidu and Oesch team. “The primal universe would have been just one hundredth its current age. It’s a sliver of time in the 13.8 billion-year-old evolving cosmos.”
Illingworth also told the agency the galaxies could have been very massive – with lots of low-mass stars – or much less massive, with Population III stars.
NASA said, as has long been theorized, that these would be the first stars ever born, made up only of primordial hydrogen and helium.
No such extremely hot, primordial stars are seen in the local universe.
The galaxies are also unusually small and compact, with spherical or disk shapes rather than grand spirals.
This discovery of compact disks at such early times was only possible because of Webb’s much sharper images in infrared light.
It said follow-up observations will confirm the distances of the galaxies – which are based on measuring their infrared colors – and that spectroscopy measurements will provide independent verification.
“These observations just make your head explode. This is a whole new chapter in astronomy. It’s like an archaeological dig, and suddenly you find a lost city or something you didn’t know about. It’s just staggering,” Paola Santini, an author of the Castellano-led paper, said.
