Astronomers Spot a Self-Destruct Mechanism in Early Giant Galaxies

Astronomers have identified a likely explanation for why many massive galaxies in the young universe appeared to stop forming stars far earlier than expected. Using combined observations from the James Webb Space Telescope and the ALMA array, they found evidence of a powerful galactic wind stripping gas from a distant system and starving it of raw material for star formation.

The study, published in Monthly Notices of the Royal Astronomical Society: Letters, focused on CRISTAL-02, a galaxy seen only about 1 billion years after the Big Bang. The object was not a single galaxy, but a late-stage merger of several galaxies. While the system was in a burst of rapid growth and forming stars at twice the rate of similar galaxies from the same era, the telescopes also detected a huge outflow of cold gas moving into intergalactic space at high speed.

According to the data, the wind is expelling material at about twice the rate of the galaxy’s star formation. At that pace, CRISTAL-02 could run out of gas and become “dead” within less than 50 million years.

Researchers say the process likely began with the merger, which funneled large amounts of gas into the center and triggered intense star formation. When the biggest stars later exploded as supernovae, they drove winds that pushed the remaining gas outward. Because nearly half of giant galaxies in the early universe show close interaction with neighboring galaxies, the team believes this self-destruct pattern may have been common, helping explain the population of unexpectedly dead galaxies seen by astronomers.