Uncovering the Origin and Evolution of Dwarf Galaxies

天体物理学中的一个长期问题是了解星系在其一生中是如何形成和发展的。这样的理解对于揭开我们宇宙的历史和洞察我们银河系的起源是必要的。许多研究项目都集中在解开这些谜团上。对附近矮星系和遥远星系的观测掌握了宇宙最初10亿年期间星系形成性质的线索，这些首批星系正在被哈勃太空望远镜探测到，并将随着詹姆斯·韦伯太空望远镜于2018年投入使用而得到进一步阐明。为了准确地解释和连接这些近距离和远距离的星系观测，考虑整个恒星形成历史的精确计算机模拟是必不可少的。该项目的目的是对附近的矮星系和遥远的超扩散星系的形成过程进行详细的计算机模拟。这些模拟将跟踪矮小星系的完整恒星形成历史，包括它们最早的恒星和银河系祖先。该项目满足了国家发展美国在天体物理学方面的科学领导地位的需要。该项目还将通过直接培训学生学习计算天体物理、高性能计算和软件工程来加强美国的科学队伍，使这些学生能够在竞争激烈的就业市场中脱颖而出。此外，研究人员的研究活动将被整合到K-12学校和其他公共场所的天体物理学教学中，如天文馆、电视节目和在线学习环境，在那里观众可以直观和直观地消化计算天体物理学的最新进展。从技术上讲，这个项目有以下目标：(1)探索星系团环境中超扩散星系的形成场景，并确定它们是否与矮小球状星系的形成序列有关；(2)构建新颖、高效和准确的辐射传输方法；(3)将矮星系形成和演化的高红移环境与今天的特征-恒星形成历史、金属丰度分布函数、恒星运动学和[α/Fe]vS。[Fe/H]演化；以及(4)确定第一批恒星和矮小星系中的贫金属星之间的化学联系。该项目将支持混合辐射传输解算器的开发，该解算器结合了射线追踪法和矩方法的优点。这种方法将被用于对孤立的矮星系进行一系列辐射流体力学模拟，从单个质量不含金属的恒星开始，在它们完全形成恒星之后。在该项目过程中产生的模拟数据以及各种数据产品将通过新成立的国家数据服务处向公众提供。这些数据将被天体物理学研究界使用，并将使研究人员能够解决比这个项目本身更广泛的问题。

A longstanding problem in astrophysics is to understand how galaxies form and develop throughout their lifetimes. Such understanding is necessary to uncover the history of our Universe and to gain insight into the origin of our own Milky Way Galaxy. Many research projects are centered on unraveling these mysteries. Observations of nearby dwarf galaxies and of very distant galaxies hold clues about the nature of galaxy formation during the first billion years of the Universe, and these first galaxies are being detected by the Hubble Space Telescope and will be further elucidated with the commissioning of the James Webb Space Telescope in 2018. To accurately interpret and connect these nearby and very distant galaxy observations, precise computer simulations that consider the entire star formation history are essential. The purpose of this project is to make detailed computer simulations of the formation process of nearby dwarf and distant ultra-diffuse galaxies. These simulations will track the complete star formation history of dwarf galaxies including their earliest stellar and galactic ancestors. This project meets the national need to develop US scientific leadership in astrophysics. This project will also strengthen the US science workforce by directly training students in computational astrophysics, high performance computing, and software engineering, which will enable these students to excel in a competitive job market. In addition, the investigators' research activities will be integrated into the teaching of astrophysics in K--12 schools and other public venues, such as planetariums, television shows, and online learning environments, where the audience can digest the latest advances in computational astrophysics in a visual and intuitive manner.More technically, this project has the following goals: (1) to explore formation scenarios for ultra-diffuse galaxies in cluster environments and to determine whether they are related to the formation sequence of dwarf spheroidal galaxies; (2) to construct novel, efficient, and accurate methods for radiation transport; (3) to correlate the high-redshift environment of dwarf galaxy formation and evolution to present-day characteristics---star formation histories, metallicity distribution functions, stellar kinematics, and [alpha/Fe] vs. [Fe/H] evolution; and (4) to determine the chemical connection between the first stars and metal-poor stars in dwarf galaxies. This project will support the development of a hybrid radiation transport solver that incorporates the advantages of both ray tracing methods and moment methods. This method will be utilized in a suite of radiation hydrodynamics simulations of isolated dwarf galaxies, following their complete star formation, starting with individual massive metal-free stars. The simulation data produced during the course of this project, as well as various data products, will be made publicly available through the nascent National Data Service. These data will be usable by the astrophysical research community and will enable researchers to address a much broader range of questions than this project alone.