RUI: Clocking the formation of today's largest galaxies: Wide Field Integral Spectroscopy of Brightest Cluster Galaxies and their surroundings

RUI：记录当今最大星系的形成：最亮星团星系及其周围环境的广域积分光谱

• 批准号: 1814375
• 负责人: Louise Edwards
• 金额: $ 19.9万
• 依托单位: California Polytechnic State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1814375&HistoricalAwards=false
• 关键词: RUI; Clocking; formation; today; largest

Mass in the universe is not smoothly distributed. Maps of nearby galaxies show that they are clustered and that these clusters are separated by large voids, where little matter is present. Each cluster has one galaxy that is the brightest. Curiously, these Brightest Cluster Galaxies (BCGs) are often found at the center of their host cluster, and often contain the oldest and reddest stars around. One outstanding question in the field of extragalactic astronomy is the following: How and when do galaxies build-up their mass? This project will measure the ages and chemical compositions of BCGs from their cores to their outskirts. It will also calculate how long it would take a BCG to grow by merging with nearby systems. The results will help astronomers discriminate between various galaxy evolution scenarios. Imaging spectroscopy (IFU) of 25 local cluster galaxies and their nearby companions will be collected and analyzed. In addition to doubling the sample of IFU studied BCGs and companions, wide field observations obtained from this work represent the first spectroscopic study of a sample of intra-cluster light (ICL). Focusing on the local universe means that its components can be studied in exquisite detail. To help elucidate the nature of the BCG and its formation, the objectives for the period of proposed work are to determine mechanisms and timescales that govern stellar mass build-up in the sample. The main deliverables include: 1) Maps of the kinematic properties and stellar populations of the BCGs, the close companions and the ICL. The location of the oldest and youngest stars within the galaxies can lend credence to whether or not the galaxies formed inside out. Whether the BCG is coeval with the intra-cluster light can be determined if the two have similar stellar populations, and if the surface brightness profile breaks; 2) Estimates of the timescale and relative contribution to the recent stellar mass buildup of BCGs and the ICL from major and minor mergers; 3) Constraints on the amount of any new or ?in situ? stellar mass buildup. This can be determined by examining the stellar populations, from searching for wet minor merging, or looking for cooling from a hot halo. Determining the properties of these local systems will provide powerful constraints for cosmological models and will form an important comparison sample for higher-redshift BCGs already being compiled. Undergraduates will be heavily involved in every aspect of this project. Through performing their research with cutting edge data, visiting a national observatory site, and presenting their work to colleagues they will experience training in the technical and social skills required to enter STEM fields as graduate students or in industry.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.

宇宙中的物质并不是均匀分布的。附近星系的地图显示，它们是聚集在一起的，这些星系团被大空洞隔开，那里几乎没有物质存在。每个星团都有一个最亮的星系。奇怪的是，这些布里渊星系团星系团（BCGs）通常位于其宿主星系团的中心，并且通常包含周围最古老和最红的恒星。河外天文学领域的一个突出问题是：星系如何以及何时积累质量？该项目将测量从核心到外围的BCGs的年龄和化学成分。它还将计算BCG通过与附近系统合并来发展需要多长时间。这些结果将有助于天文学家区分各种星系演化场景。将收集和分析25个本星系团星系及其邻近伴星的成像光谱（IFU）。除了将IFU研究的BCGs和同伴的样本加倍之外，从这项工作中获得的宽视场观测代表了对团簇内光（ICL）样本的第一次光谱研究。 专注于局部宇宙意味着它的组成部分可以被细致地研究。为了帮助阐明BCG的性质及其形成，拟议工作期间的目标是确定样品中恒星质量积聚的机制和时间尺度。主要成果包括：1）BCGs、近伴星和ICL的运动学性质和星族分布图。星系中最古老和最年轻恒星的位置可以证明星系是否由内而外形成。是否BCG是coeval与集群内的光可以确定，如果这两个有类似的恒星种群，如果表面亮度剖面打破; 2）估计的时间尺度和相对贡献，最近的恒星质量建设的BCGs和ICL从主要和次要的合并; 3）限制任何新的或？在原地？恒星质量的积累这可以通过检查恒星的数量来确定，从寻找潮湿的小合并，或寻找热晕的冷却。 确定这些局域系统的性质将为宇宙学模型提供强有力的约束，并将为已经编译的高红移BCGs形成一个重要的比较样本。本科生将积极参与这个项目的各个方面。通过使用尖端数据进行研究，参观国家天文台站点，并向同事展示他们的工作，他们将体验到作为研究生或工业进入STEM领域所需的技术和社交技能的培训。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Clocking the formation of today’s largest galaxies: wide field integral spectroscopy of brightest cluster galaxies and their surroundings

• DOI: 10.1093/mnras/stz2706
• 发表时间: 2019-09
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: L. Edwards;Matthew Salinas;S. Stanley;Priscilla E. Holguin West;Isabella L. Trierweiler;H. Alpert;P. Coelho;Saisneha Koppaka;G. Tremblay;H. Martel;Yuan Li