Some of the most luminous objects observed in the universe are associated with black holes accreting near or above the Eddington mass accretion rate. Computer simulations have contributed greatly to our understanding of this accretion, and general relativistic (GR) magneto-hydrodynamic (MHD) codes have been developed and applied widely. However, most methods do not include radiation, and the few that do can handle only limited regimes of optical depth. This project will develop a GR radiation MHD (GRRMHD) code that can handle all optical depths, and use it to study a suite of problems related to luminous accretion disks. The research group already has a radiation module developed for GR hydrodynamics, which they will add into their existing GRMHD code. While that code development is underway, the team will study hydrodynamic disks with radiation and viscosity using their pre-existing methods. Once the new technique is ready, it will be used for work on radiative magnetized disks, focusing on the structure of thin and thick radiation-dominated disks, the role of instabilities in these disks, and the generation of winds and jets by radiative acceleration. The team has some in-house computer capacity for code testing and less demanding computations, but production runs will use NSF's XSEDE supercomputer resources.
This study will improve our understanding of these high-luminosity accretion flows, and even though the work is very technical, the major advances it represents should spark public interest. The results will help to interpret the observational data that has been collected over the years, and will be very valuable for modeling quasar mode feedback in studies of galaxy formation and evolution. The principal researcher has a strong track record in mentoring young scientists, especially women, and will actively seek opportunities to involve more of them in this research.
