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、质量最小的星系，但它们是天体物理学中几个重要问题的核心，包括恒星形成和化学富集、它们作为大型星系“构件”的作用，以及作为负责电离星系间氢的主要候选者。不幸的是，矮星系也是星系类型中暗物质与普通物质比例最大的星系，结束了宇宙所谓的“黑暗时代”。矮星系主要来自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 500 万秒差距内的星系群中的数百个矮星系。它还将支持三名研究生，并与亚利桑那州图森的一所少数族裔社区学院建立持续的合作伙伴关系，研究人员计划调查矮星系群体。局部体积以及可观测宇宙中途的体积将使用两个半球的宽视场、高分辨率、多目标摄谱仪和在 NSF 支持下构建的新积分场单元 (IFU) 摄谱仪 - 积分场来完成。麦哲伦单位 (IFUM) - 具有独特的可配置空间和光谱分辨率模式，用于观察这些区域中的矮星系。主要科学目标包括 1) 绘制暗物质晕图。银河系卫星通过多历元光谱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，包括那些以显示出重度富集的恒星为主的恒星r-处理来自中子星合并等罕见事件的元素；3）将新光谱与地面和天基成像相结合，以量化卫星群的丰度、体积速度、内部化学动力学和质量金属丰度关系局部体积中银河系类似物的周围；4) 首次测量 z ~ 2 处透镜状矮星系内的恒星形成率、金属丰度和内部运动学。所得样本将为将附近的矮星系群体放入其中提供第一个基础一个真正的宇宙学背景，使关于矮星系形成和演化的第一个强有力的结论不会受到我们在本地组中的地位的影响。该奖项反映了 NSF 的法定使命，并已通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。

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