Galaxies are commonly thought to acquire much of the gas that fuels star formation through streams of cold gas that flow along filaments of larger-scale structure. However, the universe’s largest galaxies appear to have a different gas supply: precipitation of cold clouds out of hot circumgalactic gas via radiative cooling and condensation. I will present both observational and theoretical support for the precipitation model in large galaxies and show how it may apply to galaxies of all masses. One of the attractive features of the precipitation model is that it makes observationally testable predictions about the state of the circumgalactic medium, if most star-forming galaxies are indeed in a precipitating state.
Host: Michael McDonald