Astronomers using the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) have identified a high-speed “galaxy-killing” wind in the distant galaxy CRISTAL-02, a discovery that explains why many massive galaxies in the early universe ceased star formation prematurely. Research published in Monthly Notices of the Royal Astronomical Society: Letters suggests that violent galactic mergers trigger these outflows, effectively stripping galaxies of the gas required to create new stars.
Why do early galaxies stop forming stars so quickly?
Galaxies in the early universe often “die” because they exhaust their fuel supply through rapid, frenzied star formation. According to lead author Rebecca Davies of the Swinburne University of Technology, these dense, active regions experience frequent collisions. When the largest stars reach the end of their life cycles, they explode as supernovas, creating powerful winds that blast essential cold gas out of the galaxy and into intergalactic space.
CRISTAL-02 is ejecting material at a rate twice as fast as it is forming new stars. Scientists estimate that if this rate continues, the galaxy could cease all star formation in less than 50 million years.
How does CRISTAL-02 function as a case study?
CRISTAL-02 provides a clear look at the mechanics of galactic “death” just one billion years after the Big Bang. Observations from the ALPINE-CRISTAL-JWST survey show that the system is actually composed of multiple galaxies in the final stages of a merger. This collision funnels gas toward the center, sparking a massive growth spurt. While this leads to high star-formation rates—twice that of comparable galaxies—it ultimately seals the galaxy’s fate by accelerating the depletion of its gas reserves.
Are these “galaxy-killing” winds common?
Data suggests that these winds are a widespread phenomenon, not an anomaly unique to CRISTAL-02. According to the research team, nearly half of all massive galaxies observed in the early universe were interacting with nearby companions. This high frequency of mergers implies that many of the earliest giant galaxies may have been architects of their own decline, burning through their resources and ejecting their remaining gas during their most active stages of growth.
To understand how galaxies evolve over billions of years, astronomers compare current “dead” galaxies in the local universe with these early, rapidly maturing examples. Look for updates from the JWST mission page to see how newer surveys compare to the ALPINE-CRISTAL data.
Frequently Asked Questions
What defines a “dead” galaxy?
A galaxy is considered dead when it has largely ceased the formation of new stars. In the early universe, this status is surprising because these galaxies were expected to be in their most active growth phases.
How do supernovas stop star formation?
Supernovas from massive stars generate high-speed winds that physically push cold gas—the raw material for star formation—out of the galaxy’s reach.
Is CRISTAL-02 a single galaxy?
No. Research indicates it is a system of multiple galaxies currently undergoing a merger, which is the primary driver of its extreme star-forming activity and subsequent gas blowout.
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