JWST captures the most chemically "primitive" galaxy in the ancient universe
https://www.livescience.com/space/astronomy/astonishing-james-webb-telescope-spots-the-most-chemically-primitive-galaxy-in-the-ancient-universe
Thanks to Webb's advanced infrared instruments and spectrometers, scientists can now peer behind this veil and see how galaxies have evolved since the earliest cosmological epochs. In a recent discovery, an international team of astronomers used Webb and the gravitational lensing technique to capture a rare look at LAP1-B, an ultra-faint galaxy that existed 800 million years after the Big Bang. Using Webb's spectrometers, the team was able to definitively characterize this galaxy, revealing it to be the most metal-poor galaxy in the early Universe observed to date.
In the immediate aftermath of the Big Bang, the universe contained only light elements such as hydrogen and helium, while the elements necessary for life (carbon, oxygen, etc.) were absent. These elements were forged in the interiors of the first generation of stars (Population III), which were then dispersed when these stars went supernova and blew off their external layers. For decades, astronomers have been hoping to find these stars so they could witness the moment they began seeding the Universe with heavier elements. This has been problematic since the earliest galaxies that hosted Population III stars appear so small and faint.
As a result, determining their chemical makeup through spectroscopy was thought to be nearly impossible until now. The work of Nakajima builds on initial detections of LAP1-B by adding JWST spectra to the picture, revealing a record-low oxygen abundance (1/240th that of the sun). When combined with an elevated carbon-to-oxygen ratio and a dominant dark matter halo, these findings suggest that LAP1-B is a progenitor to the fossil galaxies found near the Milky Way. Astronomers have been searching for these "ancestor" galaxies, making LAP1-B a historic window into the earliest stages of galaxy formation.