Collaborative Research: The Destruction and Growth of Halo Clouds

In order for a galaxy to form new stars, the galaxy gathers more hydrogen gas. This gas is thought to rain down onto the galaxy, and indeed, gas clouds of different shapes and sizes are already found around the Milky Way galaxy. Because we see a single snapshot in time, the fate of these gas clouds is not actually known. This project will determine whether the hydrogen clouds grow as they fall into the galaxy as star formation fuel, or if the clouds will be scattered and destroyed as they fall. The investigators will compare computer simulations of clouds moving towards a galaxy to new observations of clouds near the Milky Way. Students will be trained how to conduct scientific research, and the observations will be shared with the public. The physical processes behind the destruction and growth of cool gas clouds in a hot medium is a long standing astrophysical problem. An ideal testing ground for recent theoretical advances is in our own Milky Way, in particular in the halo of our Galaxy, where discrete clouds can be easily isolated, are largely separate from the process of star formation, and are well observed. Detailed comparisons will be made, in the observational plane, of new high-resolution observations of halo clouds to high-fidelity magnetohydrodynamic simulations of the cloud destruction and growth. To complete the comparison between the simulations and observations, a library of simulated clouds with varying physical conditions will be created, and a suite of observational data on clouds with distance constraints will be prepared. The simulated clouds will be put onto the observational plane to compare the spatial morphologies and velocity structures. In addition to the research experiences for students, the project will develop a science service learning course that will teach undergraduates better methods for explaining scientific research to the local community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.