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

合作项目：矮球状星系的内部运动学：它们包含暗物质吗？

• 批准号: 9223967
• 负责人: Edward Olszewski
• 金额: $ 18.08万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-06-15 至 1999-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9223967&HistoricalAwards=false
• 关键词: Collaborative; Project; Internal; Kinematics; Dwarf

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. Mario Mateo of the University of Michigan at Ann Arbor (AST 9223968).

一系列广泛的成像和光谱观测和分析，旨在测试和测量矮人球形星系中推定的暗物质的分布，将在本研究赠款中进行。 Leo I和Leo II系统中恒星的速度色散或特征宽度将首次测量。 这些是确定在其他矮人球形星系中测得的大速度分散体是由潮汐或暗物质的存在引起的。 已经为Ursa Minor，Draco和Sextan Dwarf星系收集了多纤维光谱数据。 这些数据与Fornax星系的棘轮数据结合在一起，并与新的观察结果相结合，将确定这些星系的重力潜力，而不仅仅是它们的质量。 在评估矮人球星系的质量与光比时，距离不包含暗物质的遥远光环球形簇NGC2419的质量与光比的测量将提供必要的比较。 已经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，将进一步观察一些没有光学对应物的有趣无线电来源。 该项目是与密歇根大学Ann Arbor大学的Mario Mateo博士（AST 9223968）的合作项目。