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”星系包围，它们绕着我们的星系运行，偶尔也会与我们的星系相撞。 我们是大型星系“本地群”的一部分，每个星系都有自己的矮星系群。 天文学中尚未解答的重要问题之一是这些星系是如何形成的以及它们如何随时间变化。 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拥有比我们观察到的更多数量的矮卫星。 为了检验这是普遍存在的还是仅仅是我们当地群体的财产，该计划将对我们最近的两个银河邻居周围的区域进行详细的普查。 他们将调查两种类型的星系——螺旋星系（如银河系）和大型椭圆星系——然后测量这些新发现系统的基本特性。这涉及三个机构之间的合作，并将使用一些最大和最好的地面望远镜。 所有三位 PI 都积极参与教育和公共宣传活动。 PI Sand 所在的德克萨斯理工大学拥有一个新的天体物理学研究小组和本科生集中地。 该提案中的科学知识将有助于建立 TTU 的天体物理学计划，并影响更大的拉伯克社区。 特别是，两名天体物理学本科生将在加州度过暑假，为该项目进行研究，使他们能够与更大的天体物理学界互动。 PI Guhathakurta 非常积极地参与多个为高中生提供指导和研究经验的项目。 三位 PI 以及一名博士后研究员和学生将解决观察到的与银河系和 M31 相关的微弱矮星系的缺乏问题（比较 Lambda-CDM 对小规模结构形成的预测）。 他们将利用麦哲伦和凯克望远镜进行全景成像研究，测量NGC 253（丝状环境中的类似银河系的螺旋星系）和NGC 5128（一个巨大的中央椭圆星系）中的恒星流和矮星系含量。 他们还将使用 Keck+Diemos 和新开发的加法技术来获取潮汐流和矮星系的光谱。 如果成功，这将首次在本地群体之外进行运动学和金属丰度研究。