Professor of the Graduate School, Professor Emeritus of Physics, Astronomy
My research interests are in experimental astrophysics. My research group and I are studying the physical processes and the evolution of active galaxies and in particular of their central regions. One key issue we have been pursuing is the question whether the accretion onto massive black holes, or star formation powers active and luminous galaxies. For instance, in one class of very luminous galaxies we were recently able to demonstrate from mid-infrared spectroscopy on the Infrared Space Observatory (ISO) that enormous bursts of star formation triggered by the collision of galaxies can produce quasar-like luminosities in the infrared. Such galaxies were apparently much more common in the past than in the local Universe. We are also engaged in testing the paradigm that active galactic nuclei indeed all contain massive black holes. In the nucleus of our own Galaxy we were able to show from near-infrared imaging observations of the motions of individual stars in the central few light days that there must be a million solar mass, central black hole. Such key science goals have been driving our experimental program. We have been developing novel instrumentation, mainly in the infrared and submillimeter range, for large ground-based, airborne and space telescopes. We have been developing sensitive infrared spectrometers and imagers across the entire 1-1000mm band. We are active in the area of adaptive optics with laser stars.