James Webb Space Telescope finds candidates for earliest galaxies

Images from the James Webb Space Telescope (JWST) have helped scientists find candidates for some of the earliest galaxies seen to date. 

GLASS-z13, or GL-z13, was found by combing through data from the GLASS (Grism Lens-Amplified Survey from Space) and the Webb Telescope Cosmic Evolution Early Release Science (CEERS) early release programs, hunting for the most distant galaxies. 

"We found two stand-outs, which show the classic hallmark of being at ridiculous redshifts – they go from well-detected to zero rather abruptly," Rohan Naidu, of the Harvard Center for Astrophysics, tweeted on Wednesday. 

According to the European Space Agency (ESA) – an international partner on the JWST with NASA and the Canadian Space Agency (CSA) – the term "redshift" refers to how the wavelength of light is stretched and seen as "shifted" toward the red part of the electromagnetic spectrum. The amount of redshift is symbolized by the letter "z." 

The higher the redshift, the farther away – and back in time – the source. In this case, the redshifts of 11 and 13 mean that we can see these two galaxies as they existed more than 13 billion years ago.

"These galaxies potentially push our cosmic frontier to only ~300 million years after the Big Bang!!!" Naidu noted. 

GLASS-z11 is also a candidate under review.

NASA says that most galaxies are between 10 billion and 13.6 billion years old and that the universe is about 13.8 billion years old.

GN-z11 and HD1 were the farthest galaxies previously known in our universe, per EarthSky. 

Naidu is an author of a new paper on the preprint server arXiv that is still being peer-reviewed. 

"We're potentially looking at the most distant starlight that anyone has ever seen," he told AFP, noting that other astronomers who worked on the same data had reached similar conclusions.

"Astronomy records are crumbing already, and more are shaky," tweeted NASA's chief scientist Thomas Zurbuchen, in response to the research. "Yes, I tend to only cheer once science results clear peer review. But, this looks very promising!"

However, others are reportedly hesitant to crown GL-z13 as the "oldest."

While it existed billions of years ago, scientists are looking at a time when the universe was very young. 

"It is potentially the most distant galaxy ever, but we can't tell if it is the oldest," Naidu said in an email to Vice. "Specifically, we might be observing it as it was ~300 [million years] after the Big Bang. It could have just formed recently, or could have formed even farther back – we can't quite tell yet."

"We would like to confirm it as the *most distant* known galaxy via spectroscopy," he added.


The scientists note that more study will be needed to confirm their findings.

And, with additional observations underway, all the galaxies imaged by the JWST will help experts to understand more about the first galaxies in the universe.

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