Collaborative Research: The Circumgalactic Medium: Understanding Observations from Theory

星系最初是如何形成的，以及它们在一生中是如何变化的，这是天体物理学中最不被理解的问题之一，而理解星系的形成和生命周期是发展最广泛的天文学视角了解宇宙如何演化到现在状态的关键。许多项目都集中在解开这些谜团上。这个项目的重点是了解环星系介质(CGM)，以揭示它在星系生命周期中的作用。PI丘吉尔将根据他的课程《进入最终的前沿》来扩展他之前的更广泛的影响计划。这门课程将学生与美国太空港和新墨西哥州拉斯克鲁塞斯快速增长的航空航天和旅游业联系起来。特别强调为占新墨西哥州学生总数45%的少数族裔学生创造与STEM相关的机会。两名研究生将在新墨西哥州获得资助。皮查尔顿计划将她成功的科幻、互动、网络天文学课程转变为视频游戏，教授K-12年级的学生，同时达到宾夕法尼亚州STEM天文学标准。该项目将支持两名预选的有技能和天赋的学生构建游戏，并将其整合到当地学校。一名研究生将在宾夕法尼亚州得到支持。CGM是通过观察和分析类星体光谱中的吸收线来理解的。然而，由于对吸收气体的实际性质视而不见，目前的分析方法还没有得到校准。也就是说，我们对CGM及其在星系演化中的作用的累积知识是基于一系列隐含的和明确的假设，这些假设仍然没有得到检验或量化。使用欧拉流体动力学N体宇宙学模拟程序HADART，该团队将使用类星体吸收线技术，结合对模拟的直接分析，研究具有各种恒星形成和反馈物理模型的高度详细的模拟星系。这些星系的病毒晕质量范围为10.5log(M/MSun)12.5，红移范围为z~0-3。该团队的目标是解决这些问题：(1)星系及其周围的气相结构与恒星形成和恒星反馈的物理模型之间的关系是什么？(2)产生符合全球星系属性的星系的模型与气态库的观测属性匹配程度如何？(3)CGM如何调节重子周期和星系演化？(4)目前的吸收线分析方法是否得出了推断的气体属性(金属活性、空间运动学分布、气相、(5)从观测分析中推断出的气体性质与实际引起吸收的气体之间的定量关系是什么？(6)它们的含义是什么，它们如何改变我们对重子循环和星系演化的理解？

Precisely how galaxies initially form and how they change throughout their lifetimes are among the least understood problems in astrophysics, and understanding the formation and life cycle of galaxies is key to developing the broadest astronomical perspective on how the Universe evolved to its present state. Many projects are centered on unraveling these mysteries. This project is focused on understanding the circumgalactic medium (CGM) to uncover its role in the life cycle of galaxies.PI Churchill will expand his previous Broader Impact program based upon his course "Into the Final Frontier." This course links students to Space Port America and the growing aerospace and tourism industry rapidly growing in Las Cruces, New Mexico. Special emphasis is placed on forging STEM related opportunities for minority students, which comprise 45% of New Mexico State's student population. Two graduate students will be supported in New Mexico. PI Charlton plans to transform her successful science fiction, interactive, web astronomy course into a video game to teach K--12 students, while achieving STEM astronomy standards for the state of Pennsylvania. This project will support two pre-selected skilled and talented students to construct the game and integrate it into local schools. One graduate student will be supported in Pennsylvania.The CGM is understood through observations and analysis of absorption lines in the spectra of quasars. However, being blind to the actual properties of the absorbing gas, present day analysis methods are uncalibrated. That is, our cumulative knowledge of the CGM and its role in galaxy evolution is based upon a host of implicit and explicit assumptions that remain untested or quantified. Using the Eulerian hydrodynamic N-body cosmological simulation code hydroART, the team will use the quasar absorption line technique, coupled with direct analysis of the simulations, to study highly-detailed simulated galaxies with various star formation and feedback physical models. The galaxies will range in viral halo mass from 10.5 log(M/Msun) 12.5 and in redshift from z ~ 0-3. The team aims to address these questions: (1) What is the relationship between the gas phase structures in and surrounding galaxies and the physical model for star formation and stellar feedback? (2) How well do models that yield galaxies matching global galaxy properties also match the observed properties of the gaseous reservoirs? (3) How does the CGM regulate the baryon cycle and galaxy evolution? (4) Do current analysis methods of absorption lines yield inferred gas properties (metallicities, spatial-kinematics distributions, gas phases, and gas reservoir masses) that are consistent with the gas being probed in the simulations? (5) What are the quantitative relationships between inferred gas properties from observational analysis and the gas actually giving rise to the absorption? (6) What are the implications and how do they change our understanding of the baryon cycle and galaxy evolution?