Dr. Sellgren will study the stellar kinematics and stellar populations in the central few parsecs of our Galaxy. Her main objective is to determine if a massive black hole is present. Its mass will depend on the difference between the total mass distribution and the stellar mass distribution inferred from the light distribution. Thus, Dr. Sellgren plans to not only derive the total mass distribution from stellar kinematics, but also to examine the effect of apparent changes in the stellar population in the central parsec on the mass to light ratio. Her study of stellar kinematics will include an improved measure of the velocity dispersion of many individual bright cool stars in the Galactic Center; a careful theoretical analysis of previously observed stellar kinematics; and a comparison of the kinematics of Galactic Center stars and stars in the galactic bulge. To understand stellar populations in the central parsec of the Galaxy, Dr. Sellgren will observe the spatial variation of the strength of the 2.3 micron absorption feature of carbon monoxide in cool stars; search for Brackett gamma absorption from hot stars, and if detected, use it for stellar kinematics; and search for water vapor and neutral sodium absorption from cool dwarf stars.
