Early Galaxy CRISTAL-02 Ejects Star-Forming Gas via Stellar Winds

A galactic collision is tearing through its own fuel supply, ejecting gas twice as fast as new stars are being born.

Galaxy Merger CRISTAL-02 Is Bleeding Star-Forming Gas

An international team of astronomers, using the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA), has observed a galaxy merger, designated CRISTAL-02, that is ejecting vast quantities of gas. Observations indicate the galaxy is losing gas at a rate approximately double its rate of star formation.

CRISTAL-02 is a galaxy system with a stellar mass of approximately 10 billion solar masses. It was observed as it appeared roughly 1 billion years after the Big Bang. The system is in the late stages of a galactic collision.

The researchers detected a plume of cold gas extending across nearly the entire length of the galaxy system. This outflow is moving at hundreds of miles per second and contains approximately 1.5 billion solar masses of gas. The galaxy is forming stars at a rate of approximately 260 solar masses per year, while the outflow is ejecting gas at a rate of more than 500 solar masses per year.

According to the study authors, the outflow is driven by stellar winds from rapid star formation and supernova explosions. These processes energize and disperse cool molecular gas.

The study notes that CRISTAL-02 is likely a merger of multiple galaxies, which triggered the burst of star formation. The authors also acknowledged that an active black hole that was inactive at the time of observation could have generated the outflow.

Co-author Andreas Faisst stated that if the outflow continues, the galaxy could exhaust its star-forming gas in less than 100 million years. This would result in a "dead" galaxy less than 1.5 billion years after the Big Bang.

Lead author Rebecca Davies noted that approximately half of early massive galaxies are interacting with other galaxies. The researchers stated that the outflow efficiency in CRISTAL-02 is roughly constant compared to a sample of 99 other similar outflows spanning 12 billion years of cosmic history. This constancy, according to the researchers, may explain the observation of massive, quiescent galaxies in the early universe.

The team hypothesizes that a future merger between the Milky Way and Andromeda galaxies in approximately 4.5 billion years may produce a similar starburst and stellar wind, potentially leading to a large quiescent elliptical galaxy.

The study was published in Monthly Notices of the Royal Astronomical Society on June 10, 2026 (Davies et al., 2026).