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: 0098435
• 负责人: Heather Morrison
• 金额: $ 13.31万
• 依托单位: Case Western Reserve University
• 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 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098435&HistoricalAwards=false
• 关键词: Collaborative; Research; Structure; Origin; Galactic

AST 0098435MorrisonThis 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 Older notions of a single, monolithic collapse of the outer Galaxy on a relatively short timescale have begun to be superseded by the idea that much of the Galaxy formed from the accretion of much smaller systems over the entire age of the Universe.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 0098435MorrisonThis是一个合作研究项目，涉及3个机构的科学家：亚利桑那大学的爱德华·奥尔西夫斯基（Edward Olszewski）博士，密歇根大学的马里奥·马特奥（Mario Mateo）博士，密歇根大学的Mario Mateo博士和Case Western Reserve University的Heather Morrison博士。 这些研究人员正在绘制我们银河系的一个迄今无法到达的地区。 他们将完成一项已经进行了几年的成像调查，并将对调查中确定的光晕明星候选者进行全面的光谱随访。 进行调查是为了直接评估积聚构成大部分银河系光环的程度。 调查的主要重点是发现居住在银河系外部部分的候选光环恒星。 调查中的光晕恒星的最终样本将允许对光晕子结构的存在施加强大的限制，如果它占发光光晕的10％至20％，很可能会提供直接证据证明该结构。 天文学家如何形成星系，正在发生深刻的变化。 外部星系在相对较短的时间尺度上的单一单层崩溃的较旧观念已经开始被这样的想法所取代，即许多星系是由整个宇宙中较小的系统的积聚形成的。 支持这种积聚驱动模型的大多数数据有些间接，并且涉及对扩展宇宙中星系如何形成的复杂模型的期望。 最近，射手座矮星银河（Dwarf Galaxy）提供了有力的证据，表明我们至少一部分光环恒星和簇来自一个积聚的卫星。 ***