UW News

Aritra Ghosh


August 14, 2024

Galaxies in dense environments tend to be larger, settling one cosmic question and raising others

A new study has found galaxies with more neighbors tend to be larger than their counterparts that have a similar shape and mass, but reside in less dense environments. In a paper published Aug. 14 in the Astrophysical Journal, the team, which used a machine-learning algorithm to analyze millions of galaxies, reports that galaxies found in denser regions of the universe are as much as 25% larger than isolated galaxies. The findings resolve a long-standing debate among astrophysicists over the relationship between a galaxy’s size and its environment, but also raise new questions about how galaxies form and evolve over billions of years.