Collaborative Research: An Archaeological Survey for Substructure in the Stellar Halos of the Nearest Massive Galaxies

合作研究：最近的大质量星系星晕下部结构的考古调查

• 批准号: 1412632
• 负责人: Puragra Guha Thakurta
• 金额: $ 6.51万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412632&HistoricalAwards=false
• 关键词: Collaborative; Research; Archaeological; Survey; Substructure

Our Milky Way galaxy is surrounded by "dwarf" galaxies that orbit and occasionally collide with our galaxy. We are part of a "local group" of large galaxies, each with its own swarm of dwarf galaxies. One of the important unanswered questions in astronomy is how these galaxies formed and how they change in time. Our current understanding of structure in the universe suggests that a large galaxy like the Milky Way should actually host a larger number of dwarf satellites than we observe. To examine whether this is universal or merely a property of our local group, this program will conduct a detailed census of the regions surrounding two of our nearest galactic neighbors. They will survey two types of galaxy - spiral, like the Milky Way, and a large elliptical galaxy - and then measure the basic properties of these newly discovered systems. This involves a collaborative effort between three institutions and will use some of the largest and best ground-based telescopes. All three PIs are active in education and public outreach. PI Sand's institution, Texas Tech University, has a new astrophysics research group and undergraduate concentration. The science in this proposal will help establish TTU's astrophysics program and reach out to the larger Lubbock community. In particular, two undergraduate astrophysics students will spend summers in California doing research for the program, allowing them to interact with the larger astrophysics community. PI Guhathakurta is very actively involved with several programs that provide mentoring and research experiences for high-school students. The three PIs, along with a postdoctoral researcher and students, will address the observed lack of faint dwarf galaxies associated with the Milky Way and M31 (compared Lambda-CDM predictions for small-scale structure formation). Using the Magellan and Keck telescopes, they will conduct a panoramic imaging study to measure the stellar stream and dwarf galaxy content in NGC 253, a Milky Way-like spiral in a filamentary environment, and NGC 5128, a massive central elliptical galaxy. They will also use Keck+Diemos and newly-developed coaddition techniques to obtain spectra of tidal streams and dwarf galaxies. If successful, this would enable kinematic and metallicity studies for the first time outside the local group.

我们的银河系被“矮人”的星系包围，这些星系轨道轨道，偶尔与我们的星系碰撞。 我们是一个大型星系的“本地群体”的一部分，每个星系都有自己的矮星系。 天文学中重要的未解决问题之一是这些星系如何形成以及它们如何变化。 我们目前对宇宙结构的理解表明，像银河系这样的大型星系实际上应该容纳比我们观察到的更多矮卫星。 为了检查这是通用还是仅仅是当地群体的财产，该计划将对我们最近两个银河邻居的地区进行详细的人口普查。 他们将调查两种类型的星系 - 螺旋，例如银河系和大型椭圆形的星系 - 然后测量这些新发现的系统的基本特性。这涉及三个机构之间的协作努力，并将使用一些最大，最好的地面望远镜。 这三个PI都活跃于教育和公共宣传。德克萨斯理工大学的Pi Sand机构有一个新的天体物理研究小组和本科专业。 该提案中的科学将有助于建立TTU的天体物理学计划，并与更大的Lubbock社区联系。 特别是，两名本科生的天体物理学学生将在加利福尼亚州度过夏天，为该计划进行研究，从而使他们与较大的天体物理学社区互动。 Pi Guhathakurta非常积极参与几个计划，这些计划为高中生提供指导和研究经验。 这三个PI以及一名博士后研究人员和学生将解决与银河系和M31相关的微弱矮星系的缺乏（比较了小规模结构形成的Lambda-CDM预测）。 他们将使用Magellan和Keck望远镜进行全景成像研究，以测量NGC 253中的恒星流和矮星系含量，这是一种在丝状环境中类似银的螺旋形，NGC 5128，这是一个巨大的中央椭圆形星系。 他们还将使用Keck+Diemos和新开发的共同技术来获取潮汐流和矮星系的光谱。 如果成功，这将使运动学和金属性研究首次在本地组之外进行。