The research activities of the astrophysics theory group are led by Tohline and Frank. Tohline's research group explores the hydrodynamical evolution of self-gravitating, astrophysical systems, particularly when the geometry of such flows demand a fully three-dimensional representation. He has studied in detail problems that relate to star formation, gas-dynamical flows in galaxies, and compact stellar objects (such as white dwarfs and neutron stars). In order to understand in a quantitatively reliable way how stars, molecular clouds, and galaxies behave during key dynamical phases of their evolution. Tohline and his students have invested a great deal of time developing nontrivial computational algorithms to simulate fully three-dimensional, self-gravitating, compressible fluid flows and to visualize the results of these flows, which often can be quite complex.
Frank's research interests focus on accretion onto compact objects including active galactic nuclei powered by supermassive black holes, cataclysmic binaries containing an accreting white dwarf, and X-ray binaries involving an accreting neutron star or a black hole. These investigations consist of modeling the hydrodynamics of the accretion flow and the properties of the observed radiation. The ultimate goal of this research program is to understand the origin, structure, and evolution of binaries containing compact objects and active galactic nuclei.
Pearson's research concentrates on deducing the observational consequences of theoretical models of accreting systems. In particular he investigates the consequences of a non-circular accretion disk that can arise either from gravitational resonances in a binary system or from the interaction of the disk with a magnetic field. He also calculates the time-dependent spectra from models that can be applied to the flickering and flaring observed in a wide range of accreting systems, e.g., young stars, compact binaries and Active Galactic Nuclei.