I am investigating the optical/NIR
properties and kinematic irregularities of AGN hosts locally and at
z~1. In collaboration with the Center for Adaptive Optics
Treasury Survey (CATS, co-PIs Max, Koo, Larkin), I combine HST ACS
imagery with Keck Laser Guide Star AO K', VLT ISAAC Ks, and NICMOS H
images. Using this multicolor photometry at ~300-500 pc
resolution, we can constrain the stellar
populations independent of dust extinction of AGN hosts at
I find that intermediate luminosity X-ray-selected AGN hosts
GOODS-South (43 < log Lx < 44) tend to have more young
Myr) stars than AGN hosts with weaker X-ray luminosity.
graduate student Anne Medling, we are using Laser Guide Star AO to
resolve the kinematic signatures of stellar Keplerian orbits about a
central black hole in the famous merger NGC6240. Using the
near-IR to penetrate the dusty obscuring media in this dual AGN, we
find a southern black hole mass of ~3-5 billion solar masses.
Adaptive Optics Instrumentation
I research technologies that will
enable diffraction-limited imaging and
spectroscopy over a wide-field (1-2') at visible wavelengths (500-700
nm) on 5-10 meter class telescopes with excellent sky coverage.
have used the Laboratory for Adaptive Optics MCAO/MOAO testbed to
obtain good R-band Strehls (20%) over a 45" field on a 10-meter
telescope, using a multi-LGS, tomographic MOAO architecture.
team has installed a visible light AO system on the 1-meter Nickel
telescope at Lick Observatory to prove several enabling technologies
on-sky, including (1) MEMS deformable mirror operation, (2) open-loop
operation of wavefront sensors, and (3) use of uplink LGS correction to
lower total required laser power.