Department of Physics and Astronomy
Kinard G01, Lecture Hall
Thursday, September 8, 4:00 pm
P. C. Stancil
Department of Physics and Astronomy and The Center for Simulational Physics
University of Georgia
X-ray Emission from Beyond the Solar System:
Uncertainties and Opportunities
Abstract: X-ray astronomy is a relatively new field which began by putting detectors above the atmosphere on balloons and sounding rockets more than fifty years ago. These early glimpses revealed X-ray emission from space in all directions. Today the field is mature with three operating space telescopes (Chandra, XMM-Newton, and Suzaku), but technological challenges still limit wavelength resolution which in turn hampers scientific understanding. X-ray emitting environments typically are classified as being either in collisional ionization equilibrium (CIE) or photoionization equilibrium (PIE) with the ionization being driven by electron collisions or some high-energy photon source, respectively. Within the last decade, X-ray astronomers began to consider a third mechanism, charge exchange (CX) due to the collision of highly charged ions with neutrals. It is highly likely, the emission from most sources involve at least two, if not all three, mechanisms and disentangling the various contributions is fraught with huge uncertainties. In this talk, I'll review the status of X-ray emission modeling focusing on the astrophysics and atomic physics of CX. I'll end with an atomic physicist's perceptive of how X-ray spectroscopy fits within the full range of astronomy (radio to gamma-ray) and prospects for the future.
Bio Sketch: Phillip C. Stancil, professor of physics and astronomy, is a leader in the application of atomic and molecular dynamics to astrophysics and astrochemistry. Characterized by a coupling of advanced computational and theoretical techniques, his work looks at the atomic and molecular collision processes that underlie important cosmic questions. By performing new calculations of collisions of sulfur and oxygen ions, Stancil and collaborators showed for the first time that Jovian X-ray emissions observed by NASA’s Chandra X-ray Observatory could be explained by ions from the moon Io colliding with Jupiter’s atmosphere. Other recent work from Stancil’s group uncovered significant errors in widely used calculations for molecular hydrogen and carbon monoxide, which could have important implications for the study of interstellar clouds.
Thursday, September 8, 2016 at 4:00pm to 5:00pm
Kinard Laboratory of Physics, G01 Kinard Lab
140 Delta Epsilon Ct., Clemson, SC 29634, USA