Collaborative Research: Dwarf Galaxies and the Nature of Dark Matter

合作研究：矮星系和暗物质的性质

• 批准号: 1313006
• 负责人: Edward Olszewski
• 金额: $ 9.86万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1313006&HistoricalAwards=false
• 关键词: Collaborative; Research; Dwarf; Galaxies; Nature

The nature of dark matter (DM) remains one of the leading unsolved problems in cosmology today, and absent any direct detection of the particles themselves, the structure of nearby dwarf galaxies remains one of the most promising avenues for learning about the temperature and self-interaction properties of DM because any deviations from the standard cold dark matter model should happen at low masses.Modern ideas regarding how galaxies form in the Universe involve some form of "hierarchical" process by which small systems progressively merged into ever larger systems like our Milky Way Galaxy. A key element of this paradigm regards how mergers proceed, which, in turn, relies on understanding the nature of the DM needed to drive the formation of galaxies within the observed lifetime of the Universe. Dwarf galaxies are the smallest, simplest entities with DM that also contain visible baryonic material in the form of stars and/or gas. As such, they---and particularly their dark halos---represent our best local analogs of the building blocks that initiated the hierarchical process. The broad goal of this project is to use empirical techniques---primarily kinematic observations of stars in nearby dwarf galaxies---to determine key properties of DM halos in these systems in a largely model-independent way.The specific aims of this project include (1) learning how DM is distributed within individual galaxies by measuring the central mass densities and core properties of DM halos, (2) exploring how the evolution of the baryonic matter may have altered the DM components in galaxies, (3) determining if DM halos are truly scale free, (4) mapping the extents of DM halos in dwarfs and understanding how their dark and visible components have merged into the greater halo of our Galaxy, and (5) laying the groundwork to reconstruct the properties of the primordial population of dwarfs that contributed to the assembly of our Galaxy. This project builds on decades of NSF-sponsored instrument building and research grants to aid our understanding of the nature of DM.The investigators will engage in educational activities with several K-12 teachers, give public talks, and participate in events such as "Ask an Astronomer." The project will also support graduate student training throughout the grant period.

暗物质（DM）的本质仍然是当今宇宙学中尚未解决的主要问题之一，并且由于缺乏对粒子本身的任何直接探测，附近矮星系的结构仍然是了解温度和自旋现象最有希望的途径之一。 DM 的相互作用特性，因为与标准冷暗物质模型的任何偏差都应该发生在低质量下。关于宇宙中星系如何形成的现代想法涉及某种形式的“分层”过程，通过该过程小系统逐渐形成合并成更大的系统，比如我们的银河系。 这一范式的一个关键要素是合并如何进行，而合并又依赖于理解在观测到的宇宙寿命内驱动星系形成所需的 DM 的性质。 矮星系是最小、最简单的 DM 实体，也含有恒星和/或气体形式的可见重子物质。 因此，它们——尤其是它们的黑暗光环——代表了我们对启动分层过程的构建块的最佳局部模拟。 该项目的总体目标是使用经验技术（主要是对附近矮星系中恒星的运动学观测）以很大程度上独立于模型的方式确定这些系统中DM晕的关键属性。该项目的具体目标包括（1）通过测量DM晕的中心质量密度和核心特性来了解DM如何在各个星系中分布，（2）探索重子物质的演化如何改变星系中的DM成分， (3) 确定 DM 晕是否真正无标度，(4) 绘制矮星中 DM 晕的范围，并了解它们的暗和可见成分如何合并到我们银河系的更大晕中，以及 (5) 为重建奠定基础矮星原始种群的特性促成了我们银河系的组装。 该项目建立在 NSF 资助的仪器建设和研究经费数十年的基础上，以帮助我们了解 DM 的本质。研究人员将与几位 K-12 教师一起参与教育活动，进行公开演讲，并参加“Ask”等活动天文学家。” 该项目还将在整个资助期内支持研究生培训。

项目成果

The Binary Fraction of Stars in Dwarf Galaxies: The Cases of Draco and Ursa Minor

矮星系中恒星的双星分数：天龙座和小熊座的例子

• DOI: 10.3847/1538-3881/aae3e4
• 发表时间: 2018
• 期刊: The Astronomical Journal
• 作者: Spencer, Meghin E.;Mateo, Mario;Olszewski, Edward W.;Walker, Matthew G.;McConnachie, Alan W.;Kirby, Evan N.
• 通讯作者: Kirby, Evan N.