James Webb Space Telescope helps researchers discover early galaxies in ‘new chapter in astronomy’
In what James Webb Space Telescope researchers called “a whole new chapter in astronomy,” the observatory helped locate two early galaxies, one of which may contain the most distant star ever seen.
In a tweet, the international team said the unexpectedly bright galaxies could fundamentally change what is known about the first stars.
The research – two papers – was published last week in the Astrophysical Journal Letters.
With only four days of analysis, the researchers found the galaxies in images from the Grism Lens-Amplified Survey from Space (GLASS) Early Release Science (ERS) program.
The scientists found that the galaxies existed between 450 and 350 million years after the Big Bang, although future spectroscopic measurements with Webb will help confirm these initial findings.
“With Webb, we were amazed to find the most distant star anyone had ever seen, just days after Webb published his first data,” Rohan Naidu, Harvard-Smithsonian Center for Astrophysics and Massachusetts Institute of Technology, told NASA about the more distant GLASS galaxy – called GLASS-z12 – believed to date back 350 million years after the big bang.
Naidu led one paper and Marco Castellano, of the National Institute of Astrophysics in Rome, Italy, the other.
The previous record holder is the galaxy GN-z11, which existed 400 million years after the big bang.
“While the distances of these early sources have yet to be confirmed by spectroscopy, their extreme luminosities are a real puzzle, challenging our understanding of galaxy formation,” said Pascal Oesch of the University of Geneva.
The observations reportedly pushed 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 earlier galaxies.
“We’ve done something that’s incredibly fascinating. These galaxies had to start merging maybe only 100 million years after the Big Bang. Nobody expected the Dark Ages to end so early,” said Garth Illingworth of the University of California, Santa Cruz. , a member of the Naidu and Oesch team. “The primordial universe would have been only about a hundredth of its current age. That’s a slice of time in a 13.8-billion-year-old developing cosmos.”
Illingworth also told the agency galaxies could be very massive – with lots of low-mass stars – or much less massive ones, with Population III stars.
NASA said, as had long been theorized, that these would be the first stars ever born, composed only of primordial hydrogen and helium.
Such extremely hot, primordial stars are not seen in the local universe.
Galaxies are also unusually small and compact, with spherical or disk shapes rather than large spirals.
This discovery of compact discs at such an early age was only possible because of Webb’s much sharper infrared images.
It said subsequent observations would confirm the galaxies’ distances – which were based on measurements of their infrared colors – and that spectroscopic measurements would provide independent verification.
“These observations just blow your mind. This is a whole new chapter in astronomy. It’s like an archeological dig, and suddenly you find a lost city or something you didn’t know about. It’s just amazing,” Paola Santini, author of the journal led by Castellano, he said.
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