Gas Accretion and the Disk-Halo Interface

This project addresses the issue of how gas flows into spiral galaxies, a process essential to support the long histories of star formation in these systems. The PI and co-PI will use the adaptive-mesh hydrodynamics code Enzo to carry out two series of simulations of gas flow into disk galaxies. The first series will consist of very high resolution cosmological simulations of galaxy halos similar to that of the Milky Way; the goal is to resolve the interface between the cold and hot phases of the gas and determine whether cold clouds condensing from the hot phase make their way to the disk. The second series will simulate a vertical column in and above the galactic disk, with the goal of determining whether and how thermal instabilities serve to channel the cooling medium into the disk. The code will also be used to construct simulated observations of emission and absorption lines arising in the cooling medium, for comparison with available spectroscopic data. The work will in part be performed by, and will include the mentoring of, a postdoctoral fellow. The postdoc, PI, and co-PI will participate in a program to train graduate students to visit middle schools to conduct interactive outreach programs, and visualizations constructed from the simulations will be made available for planetarium shows or other public venues.