The James Webb Infrared Space Telescope has discovered five candidates for the most distant protoglobular clusters known. He existed 460 million years after the Big Bang in a galaxy imaged by gravitational lensing. This discovery makes a major contribution to understanding when and how the first star clusters formed and what role they played in the reionization of the universe. A preprint of this study is available at arXiv.org. The first stars and galaxies in the universe emerged during a reionization period that began about 400 million to 500 million years after the Big Bang, producing radiation that could reionize cold neutral hydrogen in the interstellar and intergalactic medium. It is extremely difficult to find distant galaxies that existed during this time, but even more difficult is observing stellar populations, which are important in depicting the processes of star formation and galaxy cluster formation. A team of astronomers led by Angela Adamo of the Oscar Klein Center has published observations of a star cluster in the gravitational lensing galaxy SPT0615-JD1 (or “Cosmic Gem Arc”). It was discovered a few years ago using the Hubble telescope. That long, magnified image was created by the gravitational pull of the galaxy cluster SPT-CL J0615-5746, which lies between us and the galaxy. SPT0615-JD1 has a redshift of 10.2, which corresponds to the age of the Universe 460 million years. This galaxy has a young (about 38 million years old) stellar population with a total mass of 2.9 × 107 solar masses, and is characterized by very low absorption of radiation by dust and metals (about 5% of that of the Sun). The researchers discovered five different candidates for giant young star clusters measuring 1 parsec in size, located in regions less than 70 parsecs deep within the galaxy. The possible age of the cluster is between 9 and 35 million years. It is believed that star formation has been occurring in this region of the galaxy for tens of millions of years. The total mass of the cluster is about 30% of the total mass of stars in the galaxy and contributes 60% of the emission in the deep ultraviolet.

source: https://arxiv.org/abs/2401.03224#:~:text=Young%20galaxies%2C%20potentially%20responsible%20for,radiation%20and%20feedback%20are%20produced.