Optical spectroscopic observations will be used with a new extended version of Doppler tomography (called modulation tomography) to map emission sources which regularly change with time in a large selection of accreting x-ray binaries which also contain neutron stars and black holes. This technique will probe structures on a micro-arc second scale that would otherwise be impossible with more traditional imaging techniques. The theoretical models developed by Dr. Vrtilek and her co-investigators will also be converted to the Doppler coordinate frame to facilitate comparisons with the observations. The specific goal here is a better understanding of the structure of disks surrounding compact objects, possible differences between those hosting neutron stars versus black holes, and the physics of the accretion flows involved. Other activities will include further developing this technique to include sinusoidal time variations and developing models for eventual uv and x-ray tomography.
The training of a graduate student is supported who will also incorporate results from this project in a Ph.D. thesis. Undergraduate students taking part in the NSF sponsored Research Experiences for Undergraduates Program at the Smithsonian Astrophysical Observatory will also be involved. It is expected that the tomographic tools developed here will have application in many areas of astronomy, particularly with interacting binary stars.
