The James Webb Space Telescope may have already found the oldest galaxy ever seen

The James Webb Space Telescope may have already found the oldest galaxy ever seen
Written by admin

Just a week after its first images were shown to the world, the James Webb Space Telescope may have found a galaxy that existed 13.5 billion years ago, a scientist who analyzed the data said on Wednesday.

Known as GLASS-z13, the galaxy dates back to 300 million years after the big Bangsome 100 million years earlier than anything previously identified, Rohan Naidu of the Harvard Center for Astrophysics told AFP.

“We’re potentially seeing the most distant starlight anyone has ever seen,” he said.

The more distant objects are from us, the longer their light will take to reach us, so to look back into the distant universe is to see into the deep past.

Although GLASS-z13 existed in the earliest era of the Universe, its exact age is unknown, as it could have formed at any time within the first 300 million years.

GLASS-z13 was spotted in so-called “early release” data from the orbiting observatory’s main infrared imager, called NIRcam, but the discovery was not revealed in the first set of images released by NASA last week.

When translated from the infrared to the visible spectrum, the galaxy appears as a red patch with white in the center, as part of a larger picture of the distant cosmos called the “deep field.”

Naidu and his colleagues, a team of 25 astronomers from around the world, have submitted their findings to a scientific journal.

For now, the research is posted to a preprint serverso it comes with the caveat that it’s not yet peer-reviewed, but it’s already got the global astronomy community buzzing.

“The astronomical records are already falling apart and there are more unstable ones.” tweeted NASA Chief Scientist Thomas Zurbuchen.

“Yes, I tend to perk up only once the science is clear.” Peer Review. But, this looks very promising,” she added.

Naidu said that another team of astronomers led by Marco Castellano working with the same data has come to similar conclusions, “so that gives us confidence.”

‘job to be done’

One of Webb’s great promises is his ability to find the first galaxies that formed after the Big Bang, 13.8 billion years ago.

Because these are so far from Earth, by the time their light reaches us, it has been stretched out by the expansion of the Universe and shifted into the infrared region of the light spectrum, which Webb is equipped to detect with unprecedented clarity.

Naidu and his colleagues combined these infrared data from the distant Universe, looking for a telltale signature of extremely distant galaxies.

Below a particular threshold infrared wavelength, all photons (packets of energy) are absorbed by the neutral hydrogen in the Universe that lies between the object and the observer.

By using data collected through different infrared filters pointed at the same region of space, they were able to detect where these photon falls occurred, from which they inferred the presence of these more distant galaxies.

“We looked in all the early data for galaxies with this amazing signature, and these were the two systems that had by far the most convincing signature,” said Naidu.

One of them is GLASS-z13, while the other, not so old, is GLASS-z11.

“There is strong evidence, but there is still work to be done,” said Naidu.

In particular, the team wants to ask Webb managers for telescope time to carry out spectroscopy, an analysis of light that reveals detailed properties, to measure its precise distance.

“Right now our assumption of distance is based on what we don’t see – it would be great to have an answer for what we do see,” Naidu said.

However, the team has already detected surprising properties.

For example, the galaxy has the mass of a billion suns, which is “potentially very surprising, and that’s something we don’t really understand” given how little time it formed after the Big Bang, Naidu said.

Launched last December and fully operational since last week, Webb is the most powerful space telescope ever built, and astronomers are confident it will usher in a new era of discovery.

© Agence France-Presse

About the author


Leave a Comment