Since June 2019, I have been a Research Professor in the Department of Physics at Washington University in St. Louis.

Prior to this, I was a research scientist at the Chandra X-ray Science Center at the  MIT-Kavli Institute for Astrophysics and Space Research, where I conduct astrophysics research with NASA and ESA satellites, in close collaboration with ground based observers. I worked part of the Chandra-High Energy Transmission Gratings Spectrometer (HETGS) team.  Prior to working at MIT, I have been a visitor at Yale University, a postdoc at JILA (formerly the Joint Institute for Laboratory Astrophysics) at the University of Colorado in Boulder, and a postdoc at the Canadian Institute for Theoretical Astrophysics (CITA) at the University of Toronto.

Who I Am:

Research Interests:

My primary interests concern high energy phenomena as related to the physics of black holes --- stellar mass black holes in our own galaxy, as well as supermassive black holes in our own Galactic center and in the centers of other galaxies --- and neutron stars. My work has encompassed both observation and theory. My early theoretical work focused on the hydrodynamics of accretion flows, and later evolved into theories describing the implications of X-ray spectra and variability for models of jets and coronae. This theoretical work led me to pursue observational studies with the Rossi X-ray Timing Explorer (RXTE), the Advanced Satellite for Cosmology and Astrophysics (ASCA), and now more recently with the Chandra, XMM-Newton, Suzaku, Swift, and NuSTAR satellites. I also have formed close collaborations with observers working in radio, optical, and other wavelength bands.

I recently was involved in a NASA Phase A study for a new High Resolution X-ray Spectrometry mission called Arcus.


Refereed publications are here, while my complete list of publications can be found here.


Dept. of Physics, CB 1105, One Brookings Dr., St. Louis, MO 63130-4899,     +1 314 935-4162,

Curriculum Vitae & Bibliography:

PDFs of my CV and Bibliography.

Page last updated: June 5, 2019