Most galaxies are now known to harbor massive black holes in their centers, but only a small fraction of galaxies harbor Active Galactic Nuclei (AGN). Thus, it cannot be the presence of the black hole that decides whether there is AGN activity or not. Instead, it must depend on the presence of fueling or the efficiency of releasing energy into radiation. My research focuses on using radio and millimeter interferometric observational techniques to study the properties of circumnuclear gas in AGN and starbursts, and the connection between AGN and starbursts. This includes Very Long Baseline Interferometry spectroscopy and imaging of, for example, 21 cm HI absorption in radio sources, and studies of OH megamaser emission in ultraluminous infrared galaxies.
Recently I have also become interested in the physics and kinematics of masers in the Milky Way. We are investigating the occurrence of masers of different transitions in supernova remnants (including masers associated with SgrA East, close to the Galactic Center). This will allow determination of maser pumping schemes and the physical state of the gas that has been shocked by the supernova explosion.
I am also involved in the realization of the Long Wavelength Array (LWA), which will be a user-oriented aperture synthesis instrument dedicated to exploring the frequency regime between 20-80 MHz. The LWA will provide high temporal and spatial resolution to probe the transient universe at long wavelengths where previous undiscovered classes of emitters, including steep-spectrum sources, are expected. The LWA will be operated by UNM on behalf of the SouthWest Consortium (the Naval Research Laboratory, University of New Mexico, Los Alamos National Laboratories and University of Texas at Austin).