标题： halo子结构的当前和未来天文测量研究 显示英文标题

标题： Present and Future Astrometric Study of Halo Substructure

摘要： 我们着重探讨了天文学巡天如何用于研究起源于卫星系统瓦解的银河系晕子结构。射手座（Sgr）矮椭球星系潮汐流提供了一个有用的模板，用于探索自行巡天目前和未来的功能，即发现和研究子结构以及利用单独的潮汐流来探测银河系的整体性质。Sgr 流的构型特别适合测量晕的扁率，并为独立测量本动速度标准提供了手段。对于各种提议的实验，所需的自行精度完全在空间干涉任务（SIM PlanetQuest）的能力范围内。 显示英文摘要

摘要： We focus on how astrometric surveys might be exploited for the study of Galactic halo substructure originating from the disruption of satellite systems. The Sagittarius (Sgr) dwarf spheroidal tidal stream provides a useful template to explore present and future capabilities of proper motion surveys for finding and studying substructure as well as for using individual tidal streams to probe the global properties of the Milky Way. The configuration of the Sgr stream is particularly well suited for measuring the flattening of the halo and for providing an independent means for measuring the speed of the Local Standard of Rest. For the various proposed experiments, the required proper motion accuracies are well within the capabilities of the Space Interferometry Mission (SIM PlanetQuest).