Collaborative Research: Dwarf Galaxies Over Cosmic Time

合作研究：宇宙时间内的矮星系

• 批准号: 2205847
• 负责人: Mario Mateo
• 金额: $ 58.84万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205847&HistoricalAwards=false
• 关键词: Collaborative; Research; Dwarf; Galaxies; Over

Dwarf galaxies are the smallest and least massive of all galaxies. They are nonetheless central to several important issues in astrophysics, including star formation and chemical enrichment, their role as "building blocks" of large, and as prime candidates responsible for ionizing the intergalactic hydrogen left over from the Big Bang, ending the universe's so-called "Dark Ages." Dwarfs also have the largest ratio of dark-to-ordinary matter among the galaxy types. Unfortunately, our knowledge of dwarfs is mostly drawn from satellites galaxies that are close to our Milky Way galaxy. This award will support continued investigations of nearby dwarf galaxies as well as an expansion of detailed studies to the hundreds of dwarfs in galaxy groups within a radius of 5 million parsecs (aka the "Local Volume"). It will also support three graduate students and a continuing partnership with a minority-serving community college in Tucson, AZ. The researchers plan to investigate dwarf galaxy populations within the Local Volume as well as those halfway across the observable Universe. This will be done using wide-field, high-resolution, multi-object spectrographs in both hemispheres and a new Integral Field Unit (IFU) spectrograph constructed with NSF support - the Integral Field Unit for Magellan (IFUM) - with uniquely configurable spatial and spectral resolution modes to observe dwarf galaxies in these regimes. Primary science goals include 1) mapping Dark Matter halos within Milky Way satellites via multi-epoch spectroscopy that identifies short-period binary stars and efficiently samples outer regions of low member density; 2) analyzing detailed chemical abundance patterns at low metallicities characteristic of Milky Way satellites—including those dominated by stars showing heavy enrichment by r-process elements from rare events like neutron star mergers; 3) combining new spectroscopy with ground and space-based imaging to quantify the abundance, bulk velocities, internal chemo-dynamics and mass-metallicity relation of satellite populations around Milky Way analogs in the Local Volume; 4) obtaining the first measurements of star formation rates, metallicity, and internal kinematics within lensed dwarf galaxies at z ~ 2. The resulting samples will provide the first basis for placing the nearby dwarf galaxy population into a truly cosmological context, enabling the first robust conclusions about dwarf galaxy formation and evolution that are not biased by the circumstances of our position within the Local Group.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

矮星系是所有星系中最小和质量最小的。尽管如此，它们仍然是天体物理学中几个重要问题的核心，包括星星的形成和化学富集，它们作为大爆炸的“基石”的作用，以及作为负责电离大爆炸遗留下来的星系间氢的主要候选人，结束了宇宙的所谓“黑暗时代”。“在星系类型中，矮星系的暗物质与普通物质的比例也最大。不幸的是，我们对矮星的了解主要来自于靠近我们银河系的卫星星系。该奖项将支持对附近矮星系的持续研究，以及将详细研究扩展到半径为500万秒差距（又名“本地卷”）的星系群中的数百个矮星。 它还将支持三名研究生，并与亚利桑那州图森市的一所少数民族服务社区学院建立持续的伙伴关系。研究人员计划调查本地体积内的矮星系种群以及可观测宇宙的一半。这将使用两个半球的宽视场，高分辨率，多目标摄谱仪和一个新的积分场单元（IFU）摄谱仪，该摄谱仪由NSF支持-麦哲伦积分场单元（IFUM）-具有独特的可配置空间和光谱分辨率模式，以观察这些制度中的矮星系。主要的科学目标包括：1）通过多历元光谱学绘制银河系卫星内的暗物质晕，该光谱学识别短周期双星，并有效地对低成员密度的外部区域进行采样; 2）分析银河系卫星低金属丰度特征的详细化学丰度模式，包括那些由中子星星合并等罕见事件产生的r过程元素严重富集的恒星所主导的模式; 3）将新的光谱学与地面和空间成像相结合，定量分析了本体积中银河系类似物周围卫星群的丰度、体速度、内部化学动力学和质量-金属丰度关系; 4）首次获得了z ~ 2处透镜矮星系内星星形成率、金属丰度和内部运动学的测量结果。由此产生的样本将为将附近的矮星系群置于真正的宇宙学背景下提供第一个基础，使第一个关于矮星系形成和演化的强有力的结论，不受我们在本地组中的位置的情况的偏见。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查评估支持的搜索.

项目成果

Finding r-II Sibling Stars in the Milky Way with the Greedy Optimistic Clustering Algorithm

• DOI: 10.3847/1538-4357/acb93b
• 发表时间: 2022-07
• 期刊: The Astrophysical Journal
• 作者: Kohei Hattori;Akifumi Okuno;I. Roederer

Metal Mixing in the r-process Enhanced Ultrafaint Dwarf Galaxy Reticulum II*

r 过程中的金属混合增强型超微弱矮星系网状网 II*

• DOI: 10.3847/1538-3881/acad84
• 发表时间: 2023
• 期刊: The Astronomical Journal
• 作者: Ji, Alexander P.;Simon, Joshua D.;Roederer, Ian U.;Magg, Ekaterina;Frebel, Anna;Johnson, Christian I.;Klessen, Ralf S.;Magg, Mattis;Cescutti, Gabriele;Mateo, Mario
• 通讯作者: Mateo, Mario

HD 222925: A New Opportunity to Explore the Astrophysical and Nuclear Conditions of r-process Sites

• DOI: 10.3847/1538-4357/acccf3
• 发表时间: 2022-10
• 期刊: The Astrophysical Journal
• 作者: E. Holmbeck;R. Surman;I. Roederer;G. McLaughlin;A. Frebel

Uranium Abundances and Ages of r-process Enhanced Stars with Novel U ii Lines*

具有新颖 U ii 谱线的 r 过程增强恒星的铀丰度和年龄*

• DOI: 10.3847/1538-4357/acb8af
• 发表时间: 2023
• 期刊: The Astrophysical Journal
• 作者: Shah, Shivani P.;Ezzeddine, Rana;Ji, Alexander P.;Hansen, Terese T.;Roederer, Ian U.;Catelan, Márcio;Hackshaw, Zoe;Holmbeck, Erika M.;Beers, Timothy C.;Surman, Rebecca
• 通讯作者: Surman, Rebecca