The COS-Halos Survey


We are an international research group studying the diffuse, invisible gas medium surrounding galaxies. We use the Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, and an array of big telescopes on the ground, to probe and weigh this gas and examine its role in how galaxies form and why they look the way they do.


This site, like galaxies themselves, is permanently under construction.

Graphic credit: NASA/STScI/Ann Feild