James Webb peers even further back in time to reveal most distant galaxies

From early on in its scientific operations, James Webb has used this method to break records by observing the most ancient galaxies ever observed.

For the new observations, the scientists measured the redshift of the light observed by Webb and found that it was at the extreme end of the spectrum, stretched all the way into the infrared end of the spectrum.

The analyses show that the galaxies present in the new observations existed when the universe was less than 350 million years old. 

Webb used its ​​near-infrared camera (NIRCam) and Near-Infrared Spectrograph (NIRSpec) instrument to detect a total of four new ancient galaxies. These have been dubbed JADES-GS-z10–0, JADES-GS-z11–0, JADES-GS-z12–0, and JADES-GS-z13–0. JADES stands for "JWST Advanced Deep Extragalactic Survey."

New galaxy observations a "tremendously exciting achievement"

After measuring the redshift of the ancient galaxies, the astronomers confirmed their findings using spectroscopy.

"It was crucial to prove that these galaxies do, indeed, inhabit the early universe. It's very possible for closer galaxies to masquerade as very distant galaxies," Emma Curtis-Lake, a co-author of one of the new studies and an astronomer at the University of Hertfordshire in England explained in ESA’s press statement.

"Seeing the spectrum revealed as we hoped, confirming these galaxies as being at the true edge of our view, some further away than Hubble could see! It is a tremendously exciting achievement for the mission," Curtis-Lake continued.

The researchers used spectroscopy to detect an abundance of elements including hydrogen and helium and a scarcity of heavier elements like oxygen, nitrogen, and carbon. Galaxies in the early universe are known to be composed mainly of hydrogen and helium, meaning astronomers could use these observations to confirm their redshift findings.

Using these methods, the scientists confirmed that the newly-discovered galaxies have a redshift of between 10.3 and 13.2, making them the oldest and most distant galaxies ever observed.

"For the first time, we have discovered galaxies only 350 million years after the Big Bang, and we can be absolutely confident of their fantastic distances," co-author and NIRCam science team member Brant Robertson said in the statement. "To find these early galaxies in such stunningly beautiful images is a special experience."