The James Webb Space Telescope has made yet another groundbreaking discovery, as it has spotted the second and fourth most distant galaxies ever seen. This amazing find supports the basic picture of galaxy formation as described by the Big Bang theory.
The discovery was made possible thanks to a massive gravitational lens in the form of the galaxy cluster known as Abell 2744, nicknamed Pandora’s Cluster. Located about 3.5 billion light years away from us, the immense gravity of the cluster warps the fabric of space-time, magnifying the light of more faraway galaxies.
Bingjie Wang, a member of the JWST UNCOVER team, used the telescope to search for early galaxies magnified by this cosmic lens and discovered two of the highest redshift galaxies ever seen.
Cosmological redshift, the stretching of light wavelengths due to the continuous expansion of the universe, allows astronomers to determine the distance of galaxies. Galaxies that existed just 300-400 million years after the Big Bang have had their light stretched into the infrared region of the electromagnetic spectrum, making them invisible to humans but detectable by the JWST’s equipment.
One of the discovered galaxies, UNCOVER-z13, has a redshift of 13.079, making it the second most distant galaxy known. The other, UNCOVER-z12, has a redshift of 12.393, placing it in fourth place in the all-time list of most distant galaxies.
What makes these galaxies different is their structure and size. Unlike previously discovered galaxies at similar redshifts, the UNCOVER galaxies have a different appearance, with one appearing elongated and the other looking like a fluffy ball. They are also bigger, with UNCOVER-z12 sporting an edge-on disk about 2,000 light years across, much larger than other galaxies seen in this era.
These unique characteristics corroborate the Big Bang model, which describes how galaxies began life small before growing rapidly through mergers and spurring more star formation.
Joel Leja, an assistant professor of astronomy and astrophysics at Penn State University and a co-researcher on the team, stated that the galaxies uncovered by UNCOVER are young, small, have a low abundance of heavy elements, and are actively forming stars, all of which supports the whole paradigm of the Big Bang theory.
The JWST has the ability to see even higher redshift galaxies, meaning they’d be even younger, but it didn’t detect any being lensed by the Pandora Cluster, prompting astronomers to continue their search using lensing clusters to open up new windows into the deep universe in search of some of the first galaxies.
The discovery was reported in Astrophysical Journal Letters, marking a significant milestone in our understanding of the early universe.