JWST scientists’ program ‘Sleeping Beauty’ to probe silent galaxies

The James Webb Space Telescope (JWST) has identified more than ten ancient galaxies that mysteriously halted star formation just a billion years after the Big Bang, baffling astronomers. These so-called “sleeping” galaxies offer rare insight into early galaxy evolution and challenge previous assumptions about constant star production in the early universe.

The abrupt quiescence in these galaxies is likely due to supermassive black holes emitting intense radiation, heating and dispersing the cold gases essential for star formation. Interference from larger neighboring galaxies may also contribute by stripping or heating the gas.

However, scientists believe these galaxies are not permanently dormant. According to researcher Alba Covello Paz of the University of Geneva, the galaxies may cycle through quiet periods of about 25 million years before reigniting star formation as gas cools and returns.

Surprisingly, the sizes of these galaxies vary widely—from 40 million to 30 billion solar masses — debunking the belief that early quiescent galaxies were of limited mass. This revelation broadens our understanding of galactic behavior in the early cosmos.

To delve deeper, JWST scientists have launched a follow-up program called “Sleeping Beauty”, aiming to track the evolution of these mysterious galaxies and determine whether they will reignite or remain dormant forever.