Discover the ‘Sleeping Beauty’ Galaxies: James Webb Telescope Unveils Cosmic Wonders in the Early Universe

Astronomers have recently identified 14 “dormant” galaxies that stopped forming stars within the first billion years after the Big Bang. This discovery, made with the James Webb Space Telescope (JWST), opens up new insights into how galaxies evolve over time.

So, why do these galaxies go dormant? One big reason is the presence of supermassive black holes at their centers. These black holes emit intense radiation, which can heat up or deplete cold gas essential for star formation. Nearby larger galaxies can also strip away this gas, halting the birth of new stars.

Additionally, stellar feedback can play a role. Events like supernovas and strong stellar winds can push gas out of galaxies, putting them in a temporary “quiet” phase. According to Alba Covelo Paz, the lead author of a recent study, this quiet period usually lasts about 25 million years. The expelled gas might eventually cool and return, allowing star formation to restart.

Historically, finding dormant galaxies in the early universe was unexpected. Astronomers had previously linked such pauses mainly to older galaxies. But with JWST, researchers are discovering that dormant galaxies can emerge at younger stages as well. In a recent study, astronomers found that these dormant galaxies have a wide range of masses, from about 40 million to 30 billion solar masses.

This pattern of “stop-and-go” star formation is intriguing. Many of the galaxies stopped forming stars between 10 and 25 million years before they were observed. This suggests a cycle where galaxies engage in bursts of star creation but also experience downtime. Current findings indicate that stellar feedback is likely the main trigger for these dormant periods, but there’s still a lot to learn.

In a 2024 paper, researchers discussed a shocking revelation: the first dormant galaxy discovered in the early universe had previously been observed by the Hubble Space Telescope, but its dormant state went unnoticed until JWST could analyze it in more detail.

Future studies aim to further explore these dormant galaxies. A JWST program, aptly titled “Sleeping Beauties,” will focus on understanding how long galaxies stay quiet and the dynamics of their star formation processes. As Paz notes, there’s much we still don’t know, but we’ve taken significant steps toward unlocking the mysteries of these “snoozing” galaxies.

For more on these cosmic discoveries, check out the full findings in the arXiv.

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