Kinematics of Stellar Systems: Distances, Mass Distributions, and Binary Star Frequencies

“恒星系统运动学：距离、质量分布和双星频率”AST-0098650这个项目研究了球状星团的结构、恒星含量和动力学演化，以及我们银河系矮球状伴生星系的暗物质含量。利用罗格斯法布里-珀罗成像仪可以获得的海量数据。该仪器是为数不多的能够获取广域径向速度数据的仪器之一，这些数据是解决这些挑战所必需的。将径向速度分布的法布里-珀罗测量与成员星自行分布的HST确定相结合，将得到13个球状星团的距离的直接几何测量。这些新距离的不确定性将是目前接受的值的五分之一左右。重复速度测量是发现双星最有成效的方法之一，预计数量的大幅增加将测试球状星团双星的动力学演化模型。该项目将使用三色恒星光度测量和广域成像仪来搜索与Draco矮星球状星系有关的恒星碎片的潮汐尾巴。这样发现的恒星的径向速度测量可以得出矮小球状星系的总暗物质质量和恒星从该系统中消失的速度。因此，在该奖项下所做的工作将对天体物理学的几个领域产生影响，包括河外距离尺度和矮小球状星系中暗物质的特征。

"Kinematics of Stellar Systems: Distances, Mass Distributions and Binary Star Frequencies"AST-0098650This project investigates the structure, stellar content and dynamical evolution of globular clusters and of the dark matter content of the dwarf spheroidal companion galaxies of our own Milky Way. Advantage is taken of the enormous amount of data that can be obtained with the Rutgers Fabry-Perot imager. This instrument is one of the few that can acquire the wide-field radial velocity data which are required to address these challenges. Combining Fabry-Perot measurements of the radial velocity distribution with HST determinations of the distribution of proper motions for member stars will yield direct geometrically based measures of the distances to 13 globular clusters. These new distances will have uncertainties about one-fifth as large as the currently accepted values. Repeated velocity measurements are one of the most productive ways of discovering binary stars and the greatly increased numbers which are expected will test models for the dynamical evolution of globular cluster binaries. The project will use three-color stellar photometry with the wide-field imagers to search for tidal tails of stellar debris associated with the Draco dwarf spheroidal galaxy. Radial velocity measurements of the stars thus found can yield total dark matter masses for the dwarf spheroidal galaxy and the rate at which stars are being lost from the system. Thus, the work done under this award will impact upon several areas of astrophysics including the extragalactic distance scale and the characteristics of dark matter in dwarf spheroidal galaxies.