Collaborative Research: The Structure and Origin of the Galactic Halo

合作研究：银河晕的结构和起源

• 批准号: 0098661
• 负责人: Mario Mateo
• 金额: $ 6.77万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098661&HistoricalAwards=false
• 关键词: Collaborative; Research; Structure; Origin; Galactic

AST 0098661MateoThis is a collaborative research project involving scientists at 3 institutions: Dr. Edward Olszewski, at the University of Arizona, Dr. Mario Mateo, at the University of Michigan, and Dr. Heather Morrison, at Case Western Reserve University. These researchers are mapping a region of our Galaxy that was hitherto unreachable. They will complete an imaging survey that has been underway for several years, and they will carry out a comprehensive spectroscopic follow-up of halo-star candidates identified in the survey. The survey is undertaken to directly assess the degree to which accretion has formed the majority of the Galaxy's halo. The main focus of the survey is finding candidate halo stars that inhabit the outer parts of the Galactic halo. The final sample of halo stars from the survey will allow placement of strong limits on the existence of halo substructure and will very likely provide direct evidence of such structure if it comprises more than 10% to 20% of the luminous halo. A profound change is underway in how astronomers believe galaxies, such as ours, formed. Older notions of a single, monolithic collapse of the outer Galaxy on a relatively short timescale have begun to be superseded by the idea that much of the Galaxy formed from the accretion of much smaller systems over the entire age of the Universe. Most data supporting this accretion-driven model is somewhat indirect and involves expectations of sophisticated models of how galaxies form in an expanding Universe. Recently, the Sagittarius dwarf galaxy has provided strong evidence that at least part of our halo stars and clusters have come from an accreted satellite. ***

AST 0098661Mateo这是一个涉及 3 个机构科学家的合作研究项目：亚利桑那大学的 Edward Olszewski 博士、密歇根大学的 Mario Mateo 博士和凯斯西储大学的 Heather Morrison 博士。 这些研究人员正在绘制我们银河系迄今为止无法到达的区域的地图。 他们将完成一项已经进行了数年的成像调查，并对调查中确定的候选晕星进行全面的光谱跟踪。 这项调查的目的是直接评估吸积形成银河系光晕大部分的程度。 该调查的主要重点是寻找居住在银河晕外部的候选晕恒星。 调查中的晕星最终样本将对晕亚结构的存在施加严格限制，并且如果它包含超过 10% 至 20% 的发光晕，则很可能提供这种结构的直接证据。 天文学家对像我们这样的星系的形成方式的看法正在发生深刻的变化。 关于外星系在相对较短的时间尺度内单一、整体崩溃的旧观念已经开始被这样的观念所取代，即银河系的大部分是由更小的系统在整个宇宙时代的吸积形成的。 支持这种吸积驱动模型的大多数数据都有些间接，涉及对星系在膨胀宇宙中如何形成的复杂模型的期望。 最近，人马座矮星系提供了强有力的证据，证明我们的晕恒星和星团至少有一部分来自一颗吸积的卫星。 ***