My research program centers on the use of large-scale direct numerical simulations to study the gas dynamics of a wide range of astrophysical systems, from protostars to clusters of galaxies.  Almost all of this work requires development of advanced numerical algorithms for astrophysical gas dynamics on modern parallel computer systems.  For example, I am one of the primary developers of the ZEUS code for astrophysical MHD, and more recently my collaborators and I have developed Athena, a high-order Godunov scheme for astrophysical MHD that uses adaptive mesh refinement (AMR).

Some of the research problems on which I work include: (1) hydrodynamic and MHD processes that can lead to outward angular momentum transport in accretion disks, (2) the production and propagation of highly supersonic, collimated jets from accretion disks around protostars and active galactic nuclei, (3) the properties of compressible MHD turbulence in cold molecular gas in the galaxy, (4) the time-dependent evolution of strong shocks in the interstellar medium, (5) the structure of radiatively driven winds and outflows from disks around hot stars and AGN, and (6) the effect of mergers and AGN feedback on the hot x-ray emitting gas in clusters of galaxies.

I am deeply involved in PICSciE, which provides access to high-performance computing systems on campus, and training and education in scientific computation and numerical analysis, and I have a joint appointment in the Program in Applied and Computation Mathematics (PACM).