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，最少的。尽管如此，它们仍然是天体物理学中几个重要问题的核心，包括恒星形成和化学富集，它们作为大型的“构件”的作用，以及负责电离大爆炸中造成的天际氢的主要候选者，结束了宇宙所谓的“黑暗年龄”。矮人在银河类型中的黑暗与异常比例也最大。不幸的是，我们对矮人的知识主要来自与我们银河系相近的卫星星系。该奖项将支持近矮星系的持续投资，以及在半径500万个parsecs中的银河系中的数百个矮人的详细研究扩展（又称“本地卷”）。它还将支持三名研究生，并与位于亚利桑那州图森市的一所少数族裔社区学院建立持续合作伙伴关系。研究人员计划调查本地体积中的矮星人群以及可观察到的宇宙中途的人群。这将在半球和新的积分场单元（IFU）光谱仪中使用宽场，高分辨率，多对象光谱仪完成，该光谱仪是由NSF支持构建的 - 麦哲伦（IFUM）的积分场单元（IFUM） - 具有可构型的空间和光谱分辨率模式，可观察到这些模式在这些模特中观察到达瓦尔夫星系中的矮人。初级科学目标包括1）通过多个上述光谱法绘制银色物质卫星的映射，该光谱通过多个上述光谱鉴定出短周期二进制恒星，并有效地为低成员密度的外部区域采样； 2）分析银河系卫星特征的低金属特征的详细化学丰度模式，包括由恒星主导的那些占主导地位的化学含量，表现出来自罕见事件（如中性恒星合并）的R-process元素的大量富集； 3）将新光谱与地面和空间成像结合在一起，以量化卫星种群在局部体积中的银河系类似物周围的卫星种群的丰度，散装速度，内部化学动力学和质量金属关系； 4）在Z〜2处获得恒星形成速率，金属性和内部运动学的首次测量。结果样本将为将附近的矮人星系置于真正的宇宙学上下文中，将附近的矮人星系置于一个真正的宇宙学上下文中，从而使我们的首个既定的结构都在我们的首个结论中，而不是在我们的第一个稳固的结论中，这是我们对矮星的形式构建的态度，而我们却是矮人的偏见。反映了NSF的法定任务，并通过使用基金会的知识分子和更广泛的影响审查标准评估被认为是宝贵的支持。

项目成果

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

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

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