Research
Discovery of the shortest period star, S0-102
Over the past 17 years, we have used the W. M. Keck Observatory to image the galactic center at the highest angular resolution possible today. By adding to this data set and advancing methodologies, we have detected S0-102, a star orbiting our galaxy's supermassive black hole with a period of just 11.5 years.More details...
Keck I and II laser guide stars pointing at the Galactic center
(Photo credit: Dan Birchall).
Adaptive Optics Technology
Our best views of the night sky are afforded by the world's largest telescopes, such as those at the W. M. Keck Observatory that have been equipped for the last decade with Adaptive Optics. This revolutionary hardware technology corrects for the blurring effects of the Earth's atmosphere by measuring aberrations in the wavefront of a bright guide star and subsequently adjusting the shape of a deformable mirror. These corrections can be made on either a bright natural guide star (NGS) or a laser guide star (LGS), as shown in the image.More details...
Three-color (HKL) image of the central 10'' of the Galaxy.
Stellar Populations
Adaptive optics spectroscopy has allowed for spectral identifications of bright (K < 16) stars within ~1 pc of the supermassive black hole and has revealed two very unexpected results. The first surprise was the detection of a wealth of young (< 10 Myr) stars in a region where none were expected due to the strong tidal field of the supermassive black hole and the low present day gas densities. The second surprise was the unanticipated dearth of late-type stars near the SMBH. The radial profile of these old stars is significantly flatter than that predicted by theoretical models.More details...
Black Hole Accretion
Sgr A*, the radio source associated with the central supermassive black hole,
is quite underluminous as compared to black holes at the centers of other galaxies.
However, with the increased sensitivity provided by adaptive optics, the infrared
emission from material accreting onto Sgr A* has been detected. The emission is
variable, and the luminosity of Sgr A* can increase by a factor of a few over the
stellar background during a single night.
More details...
Three-color images showing the variable emission of Sgr A*
NIRC2 Distortion Solution
We have constructed a new optical distortion model for the W. M. Keck II 10 m telescope's adaptive optics camera, NIRC2, in its narrow field mode. Using on-sky measurements of a globular cluster, we have improved the distortion solution by a factor of ~3 over the previous solutions. Download the distortion solution here.Download the distortion solution here.