The Use of Gaseous Xenon as a Detector Medium for Hard X-ray Astronomy

Hard x-ray detectors are used to study black holes, neutron stars and active galactic nuclei. In xenon gas the energy of an incident x-ray gets converted to scintillation light, the strength of which is proportional to the energy of the x-ray absorbed. In the laboratory we have been studying this process.


Long-term Stellar Monitoring

We have been measuring the "apparent brightness" of more than 1600 stars in a single field since 2003, with occasional stops to observe other fields. We acquire hundreds or thousands of images of a rich star field in a given night. This work should prove useful for the study of everything from meteors to near-earth asteroids to variable stars and foreground objects passing between us and a distant star. Much of our current effort focuses on the approximately 60 new semi-regular variable stars we have discovered in this field. We are looking for evidence of multiple pulsation modes and secular evolution in these stars. We also monitor half a dozen eclipsing binary stars in the field, looking for subtle changes in the orbital periods of these systems and we search for for rare stellar flares.


Students are an active part of this ongoing research work, leading to dozens of individual student research projects.