James Webb finds the most distant galaxy in the Universe – 04/04/2023 – Science

The James Webb Telescope has located the most distant galaxy ever identified, dating back to the initial expansion of the Universe, 320 million years after the Big Bang, according to studies published on Tuesday (4).

The first results from the James Webb Telescope (JWST), in operation since July 2022, have identified numerous “candidate” galaxies through the infrared spectrum, a wavelength invisible to the human eye that allows you to go back much further in time, that is, help to identify their ages through their luminosity.

The space apparatus has a powerful infrared observation capacity, which combined with spectroscopy – which analyzes the light of an object to determine its chemical elements – identified “unequivocally” the existence of four galaxies.

All are very distant, with ages ranging between 300 and 500 million years after the Big Bang (which occurred 13.8 billion years ago), according to two studies published in the journal Nature Astronomy.

At that time, the Universe was only 2% of its current age and was going through what scientists call the reionization period: after a phase known as the “dark age”, it returned to activity and started to produce a large amount of stars.

The most distant galaxy located by the JWST, named Jades-GS-z13-0, formed “320 million years after the Big Bang” and its light is the most distant ever observed by astronomers, Stéphane Charlot explained to AFP, from the Institute of Astrophysics in Paris, one of the authors of the study.

‘A feat’

The space telescope also confirmed the existence of the galaxy GM-z11, about 450 million years after the Big Bang, which had already been detected by the Hubble telescope.

The four galaxies observed are of very low mass, just a hundred million times the mass of the Sun, compared to the Milky Way’s 1.5 trillion times. However, they are “very active when it comes to forming stars, proportionally to their mass”, details the astrophysicist.

The formation of these stars is happening “at approximately the same pace as the Milky Way”, a speed “surprising in that early phase of the Universe”, comments the researcher.

These galaxies are, on the other hand, “very metal-poor”, a finding that confirms classical theories in cosmology that the closer they are to the origin of the universe, the less time these stars have had to form complex molecules.

The new JWST contribution is “a technological feat,” says Pieter van Dokkum, an astronomer at Yale University, in a commentary attached to the study.

“Every month” the telescope goes beyond “the frontiers of exploration”, he analyses.

In February, JWST also identified a group of six galaxies between 500 and 700 million years old after the Big Bang, apparently much more massive than expected. If their existence is confirmed by spectroscopy, it could call into question some of the theories about the formation of the Universe.