Astronomers have new insight into how young stars shape the evolution of galaxies, highlighting the powerful role of stellar “feedback” in influencing cosmic environments. In a new study, shared in a press conference at the 248th meeting of the American Astronomical Society, the researchers analyzed roughly 18,000 star-forming regions in nearby spiral galaxies using observations from the the Atacama Large Millimeter/submillimeter Array (of which the U.S. National Science Foundation National Radio Astronomy Observatory is a partner) alongside the James Webb Space Telescope and the Hubble Space Telescope. This data came from the international research collaboration, Physics at High Angular resolution in Nearby GalaxieS (PHANGS), which aims to better understand how galaxies grow and change over time.

The team found that in typical galaxies, pressure from ionized gas generated by newly formed stars drives the expansion of star-forming regions. However, whether these regions continue to grow or stall depends strongly on their surrounding environment. “When young massive stars form, they release large amounts of energy that disrupt their surroundings and push interstellar material outward,” said lead author Debosmita Pathak, a graduate student in astronomy at The Ohio State University.

This process, known as stellar feedback, plays a key role in regulating star formation and shaping the structure and chemistry of galaxies. It can either trigger the birth of new stars or halt it by dispersing the gas needed for star formation. To explore how these effects vary in extreme conditions, researchers compared normal galaxies with NGC 3256, a highly active system formed by a collision between two galaxies. They found that feedback pressures in NGC 3256 are about 100 times stronger than in galaxies like the Milky Way, creating a more turbulent and unpredictable environment.

“These measurements reveal physical conditions we haven’t been able to study before,” Pathak said. “They help us better understand the processes driving galactic evolution across different environments.” This research offers new clues about how young stars influence galaxies long before dramatic events like supernova explosions occur, and it provides a benchmark for improving models of how galaxies evolve across the universe.

Quelle: The National Radio Astronomy Observatory