Collaborative Project: The Internal Kinematics of Dwarf Spheroidal Galaxies: Do They Contain Dark Matter? (Part II of 2 Projects)

一系列广泛的成像和光谱观察和分析，旨在测试和测量矮球状星系中假定的暗物质的分布，将在这项研究资助中进行。在狮子座I和狮子座II系统中，恒星的速度色散或特征宽度将首次被测量。这些是决定在其他矮球状星系中测量到的大速度色散是由潮汐还是暗物质的存在引起的关键对象。已经收集了小熊座、天龙座和六分星矮星系的多纤维光谱数据。结合天炉座星系的梯队数据和新的观测结果，这些数据将允许确定这些星系的引力潜力，而不仅仅是它们的质量。对遥远的晕状球状星团NGC2419的质量光比的测量，将为评估矮球状星系的质量光比提供必要的比较。NGC2419被认为不包含暗物质。收集了大量的成像数据，以改善或测量这些低光度星系的结构。最后，将对一些没有光学对应的有趣射电源进行进一步的射电观测。本项目是与亚利桑那大学的Edward W. Olszweski博士合作的项目（AST 9223967）。

An extensive series of imaging and spectroscopic observations and analysis designed to test for and measure the distribution of the putative dark matter in dwarf spheroidal galaxies will be carried out in this research grant. The velocity dispersion, or characteristic width, of stars in the Leo I and Leo II systems will be measured for the first time. These are key objects for deciding if the large velocity dispersions measured in the other dwarf spheroidal galaxies are caused by tides or the presence of dark matter. Multifiber spectroscopic data have been collected for the Ursa Minor, Draco, and Sextan dwarf galaxies. Combined with echelle data for the Fornax galaxy and with new observations, these data will allow the gravitational potential of these galaxies, not just their mass, to be determined. Measurement of the mass-to-light ratio of the distant halo globular cluster NGC2419, which is thought to contain no dark matter, will provide a necessary comparison when assessing the mass-to-light ratios of the dwarf spheroidal galaxies. Extensive imaging data to improve or measure the structure of these low luminosity galaxies has been collected. Finally, further radio observations of some intriguing radio sources with no optical counterparts will be made. This project is a collaborative project with Dr. Edward W. Olszweski of the University of Arizona (AST 9223967).