The James Webb Space Telescope made an unexpected discovery

The entire region was observed for the first time using a space telescope. Hubble in 2018, and has properties that indicate it may be a site of reionization, but its components are difficult to recognize. Each star cluster is approximately parsec (about 3.26 light years), indicating that they very densewhich is approximately three orders of magnitude larger than typical young star clusters in the local Universe.

During the reionization of the Universe

The authors conclude that these results mean that star cluster formation and feedback may have shaped the properties of galaxies during the epoch reionization The universe underwent a major change that began about 379,000 years after the Big Bang.

“Reionization is one of the last major phase transitions of the Universe,” Adamo explains. “We think it started around the redshift at which we detected these star clusters, so they are found in the galaxy in the early stages of reionization.”

In our Milky Way we see ancient globular star clustersheld together by gravity and preserved for billions of years. They are old relics of intense star formation in the early cosmos, but it is not known where or when they formed. The discovery of young, massive star clusters in the Cosmic Gem Arc now provides a beautiful glimpse into this process.

“These results provide direct evidence that protoglobular clusters formed in faint galaxies during the reionization era, furthering our understanding of how these galaxies managed to reionize the universe– says Angela.

Spanish participation

Another of the authors Yolanda Jimenezresearcher from the Institute of Astrophysics of Andalusia (IAA-CSIC) and the National Observatory of Rio de Janeiro (Brazil), summarizes the findings: “These structures are the oldest star clusters ever discovered and may be the predecessors of the globular clusters that we currently have observed in our galaxy.”

“This discovery once again demonstrates how, thanks to James Webb, we are uncovering the earliest stages of the development of our Universe,” says co-author Jose Maria Diegoscientist from the Institute of Physics of Cantabria (IFCA, a joint centre between CSIC and the University of Cantabria), where a model of the gravitational lens effect was developed to understand the magnification of the arc.

“One of the questions that remains to be resolved is why we only see five double images,” he comments, “when in fact we expect six. A possible explanation is the presence dwarf galaxy unnoticed James Webb, with a lower magnification, which does not allow us to see the image in question.”

At the moment, “we are monitoring spectroscopic observations Comic Gems arc, which will help obtain more accurate physical properties of their star clusters and host galaxy,” continues Adamo. Additional studies with Webb’s participation are planned in 2025, which could bring new surprises.