Webb and ALMA Catch Galaxy-Killing Wind in the Act, Solving a Cosmic Mystery
Astronomers using the James Webb Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) have caught a distant galaxy in the act of being killed — a finding that may finally explain why so many massive galaxies in the early universe died young.
The galaxy, named CRISTAL-02, is seen as it appeared just one billion years after the Big Bang. Observations show it is blasting vast quantities of cold gas into intergalactic space, stripping away the raw material needed to form new stars. The study was published June 10 in Monthly Notices of the Royal Astronomical Society: Letters.
“Dense regions of the universe are like very active cities,” said Rebecca Davies of Swinburne University of Technology in Melbourne, the study’s lead author, in a statement. “Galaxies collide and undergo frenzied bursts of star formation. But when the biggest stars burn out, they explode as supernovas, launching powerful winds that blast away the very gas galaxies need to keep forming stars.”
CRISTAL-02 is forming stars at roughly twice the rate of similar galaxies from the same epoch. But the wind is ejecting material even faster — twice as fast as the galaxy forms stars.
“Galaxy-killing” wind measured by Webb and ALMA
“If this rapid blowout continues, the galaxy could be dead in less than 50 million years,” Davies said. “That explains the origin of the mysterious massive dead galaxies in the early universe.”
Galaxies are considered alive when they are actively forming stars and dead when star formation has largely ceased. Dead galaxies are common in the modern universe, but astronomers have been puzzled by finding large numbers of them in the early cosmos — an era when galaxies were expected to be growing rapidly.
The discovery provides the first direct observation of a galaxy-killing wind in action at the critical epoch when these massive dead galaxies first appear. The wind is driven by the same intense star formation that causes galaxies to grow, creating a feedback loop that ultimately shuts down the galaxy’s growth.
Davies believes other galaxies likely face a similar fate, undergoing bursts of intense star formation followed by sudden quenching. The findings offer a natural solution to what had become a long-standing tension between observations and theoretical models of galaxy evolution.
The research team used JWST’s infrared capabilities to peer through dust and gas to the galaxy’s core, while ALMA traced the cold gas being expelled. Together, the two observatories provided a complete picture of a galaxy in its death throes.
Sources: Space.com (Samantha Mathewson, June 11, 2026); MNRAS: Letters (Davies et al., June 10, 2026).