"These pressure measurements have not been possible before and will help benchmark physical processes driving galactic evolution."

Unlocking the Lifecycle of Galaxies: New Research Reveals How Star-Forming Regions Evolve

In a landmark study, astronomers analyzed approximately 18,000 star-forming regions in nearby spiral galaxies. Using a powerful trifecta of data from the James Webb Space Telescope, Hubble Space Telescope, and the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the PHANGS survey, the team has for the first time quantified the forces governing the birth of stars.

Key Findings

In normal galaxies, pressure from ionized gas drives the expansion of young star-forming regions. Whether these zones continue to grow or remain stagnant depends entirely on their surrounding environment, according to Debosmita Pathak, lead author and a graduate student at The Ohio State University.

This mechanism, known as stellar feedback, can influence galactic activity across multiple scales, potentially triggering or destroying star formation. The research was presented on June 17, 2026, at the 248th meeting of the American Astronomical Society in Pasadena, California.

A Stark Contrast: Starburst Galaxy NGC 3256

The team compared stellar feedback pressures in normal star-forming galaxies with those in the starburst system NGC 3256, a pair of merging galaxies about 100 million light-years away.

• In NGC 3256, stellar feedback pressures are about 100 times stronger than in Milky Way-like spiral galaxies.
• Most young star clusters there are likely powerful enough to continue expanding despite this intense pressure.
• High turbulence in NGC 3256 indicates the gas is not settled in a simple flat disk, suggesting a far less predictable interplay between star formation and its precursors.

Implications for Galactic Evolution

Pathak stated that these pressure measurements have not been possible before and will help benchmark physical processes driving galactic evolution. The results have implications for understanding star-forming region evolution in various cosmic settings, even before supernovae occur.

Pathak plans to continue this work as a visiting graduate student at IPAC at Caltech in Pasadena, California, this summer.