RESEARCH

I work with Andrea Ghez and the UCLA Galactic Center Group. My main research interest is in the dynamics of stellar populations. I study the motions of the stars at the center of the Galaxy as they orbit the supermassive black hole, Sgr A*, in order to better understand this environment and the origin of the young star cluster.

In order to measure the proper motions of stars in the dense environment of the Galactic center (GC), we require high angular resolution imaging. With Laser Guide Star Adaptive Optics (LGS-AO) at the Keck Observatory on the big island of Hawai'i, we consistently obtain sub-milliarcsecond astrometry and are able to measure proper motions with average uncertainties of ~3 km/s.

YOUNG STARS AT THE GALACTIC CENTER:

I am currently working on using kinematic measurements of the young stars in the Galactic center in order to understand their origin. Their proximity to Sgr A* is a mystery since it is difficult to invoke star formation (as we currently understand it) so close to a supermassive black hole. Approximately half of these stars are known to orbit in a clockwise disk around Sgr A* (Lu et al. 2009, Paumard et al. 2006, Genzel et al. 2000), while the other half are out of this disk. Estimating the orbital parameters from the stars' kinematics will help us better understand this "paradox of youth".

NIRC2 OPTICAL DISTORTION:

I've been involved in creating a new distortion solution for the NIRC2 narrow camera at Keck. We have significantly improved upon previous distortion solutions using observations of the globular cluster M92. We will be distributing this information to the public very soon. Please email me if you have any questions in the mean time.

MASS DISTRIBUTION IN THE GALACTIC CENTER:

For my Master's project, I measured the stellar velocity dispersion in order to understand the mass distribution in the central ~0.5 pc of the Galaxy. The supermassive black hole (~4 million solar masses) dominates the gravitational potential in the GC. However, there have been discrepancies in the past about just how much additional mass is in the inner few arcseconds of the Galaxy. To try to resolve this issue, we use high-precision proper motions of ~1000 stars in the GC. These measurements can give us a good estimate of the amount of extended mass distributed within the outermost stars measured.

Previous research:

At the University of Michigan, I worked with Professor Sally Oey on HII regions and the warm ionized medium (WIM) in galaxies from the Survey for Ionization in Neutral-Gas Galaxies (SINGG). We measured the fraction of H-alpha luminosity contributed by the WIM for various types of galaxies and studied the WIM's relationship with different star formation properties. See our paper for more details.

I also worked with Professor Robert Mathieu at the University of Wisconsin during the summer of 2005 as part of the Research Experience for Undergraduates (REU) program. My project was on the tidal circularization of stellar binaries in the open cluster, NGC 6819. See my REU webpage for details of this project.

My first project in astronomy, with Diane Paulson, involved searching for substellar mass companions to young stars, which often are neglected in radial velocity searches because the increased level of stellar activity makes detecting companions more difficult. We did not find evidence for any companions, but we report the derived stellar parameters for dozens of nearby young stars in our paper.