Stellar Kinematics and Stellar Populations in the Galactic Center

塞尔格伦博士将研究银河系中心几个秒差的恒星运动学和恒星群。她的主要目标是确定是否存在一个巨大的黑洞。它的质量将取决于总质量分布和从光分布推断出的恒星质量分布之间的差异。因此，Sellgren博士计划不仅要从恒星运动学中得出总质量分布，还要研究中心秒差距内恒星数量的明显变化对质量光比的影响。她对恒星运动学的研究将包括对银河系中心许多单独的明亮冷恒星的速度色散的改进测量；对先前观测到的恒星运动学进行仔细的理论分析；以及银河系中心恒星和银河系凸起部分恒星的运动学比较。为了了解银河系中心秒差距的恒星群，Sellgren博士将观察低温恒星中一氧化碳2.3微米吸收特征强度的空间变化；寻找来自热恒星的布兰克特伽马吸收，如果发现了，用它来计算恒星的运动学；寻找来自低温矮星的水蒸气和中性钠的吸收。

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.