Galaxy Evolution: Tidal Remnants, Outflows, and Inflows

凯瑟琳·巴格博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在圣母大学开展一项研究和教育计划。星系形成中最紧迫的问题之一是气体的吸积和反馈如何影响星系的演化。星系的演化是由星系吸积和保留气体以继续恒星形成的能力来调节的，但是物质是如何在星系内外循环的呢？最近的理论研究表明，主要电离物质可能通过星系间的细丝落入星系，但尚不清楚气体是否会在到达星系盘之前在晕中蒸发。相比之下，来自大质量恒星的反馈通过加热和电离气体来排出气体并熄灭恒星的形成。为了了解更远星系的流出和流入过程，这个项目的研究员将在本地宇宙中研究它们，在那里它们可以被详细研究。为了破译银河系环星系气体的流动，该研究员将结合威斯康星h - α映射器（WHAM）光学和哈勃太空望远镜对大麦哲伦云（LMC）流出和麦哲伦流的紫外光谱观测，以测试矮星系是否能够维持大质量星系恒星的形成，并测试为星系提供能量的气体结构的起源。麦哲伦星云离我们足够近，可以利用吸收和发射光谱的力量，使研究人员能够测量弥漫的星系周围气体的密度、温度、金属丰度、运动学和形态。通过这些观测，他将研究大麦哲伦星云的恒星外流和麦哲伦流，以确定它们的基本物理特性、电离源、范围和形态，以及它们的命运。建立一个关于银河系环境中气体流动的新视角，将为理解宇宙中远离星系的气体检测的含义提供更坚实的基础。这个项目更广泛的影响包括一个重要的教育组成部分。该研究员将为圣母大学物理系创建一个专业资源开发项目。该计划将包括年度专业发展研讨会以及补充讲习班。专业资源开发研讨会将包括与圣母大学专业发展委员会成员一起讨论传统学术和替代职业道路、网络和工作申请的主题，该委员会的成员包括Kaneb教学中心、写作中心、研究生院、学术英语中心、赖利科学中心等。每年夏天，该课程将包括三个关于简历、研究报告和求职信的研讨会，并将强调强大的沟通技巧和针对不同受众量身定制文件的重要性。物理系的研究员项目将成为整个理学院类似专业发展资源的典范。

Dr. Kathleen Barger is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Notre Dame. One of the most pressing problems in galaxy formation concerns how gas accretion and feedback influence the evolution of galaxies. Galaxy evolution is regulated by the ability of galaxies to accrete and retain gas to continue star formation, but how does matter cycle in and out of galaxies? Recent theoretical studies suggest that predominantly ionized material may infall onto galaxies through intergalactic filaments, but it is unclear whether the gas will evaporate in the halo before reaching the galactic disk. In contrast, feedback from massive stars expels gas and quenches star formation by heating and ionizing the gas. To understand outflow and inflow processes in galaxies at greater distances, the fellow in this project will study them in the local Universe, where they can be studied in detail.To decipher the flows in the circumgalactic gas of the Milky Way, the fellow will combine Wisconsin H-Alpha Mapper (WHAM) optical and Hubble Space Telescope ultraviolet spectroscopic observations of the Large Magellanic Cloud (LMC) outflow and Magellanic Stream to test if dwarf galaxies can sustain massive galaxy star formation and to test the origin of the gaseous structures feeding galaxies. The Magellanic Clouds are nearby enough to exploit the power of absorption- and emission-line spectroscopy, allowing investigators to measure the density, temperature, metallicity, kinematics, and morphologies of the diffuse circumgalactic gas. Through these observations the fellow will investigate the LMC stellar outflows and the Magellanic Stream to determine their basic physical properties, the source of their ionization, their extent and morphology, and their fate. Establishing a new perpective of the gaseous flows in our own Galactic environment will provide a firmer basis to understand the implications of gas detected far from galaxies throughout the Universe.The broader impacts of this project include a significant educational component. The fellow will create a Professional Resource Development program for the Physics Department at the University of Notre Dame. This program will consist of an annual professional development seminar along with complementary workshops. The Professional Resource Development seminar will include topics on traditional academic and alternative career paths, networking, and job applications in conjunction with members of the Professional Development Committee at Notre Dame, whose membership includes the Kaneb Center for Teaching and Learning, Writing Center, Graduate School, English for Academic Purposes, Reilly Center for Science, among others. Each summer this program will include three workshops on Curriculum Vitae, research statements, and cover letters and will stress the importance of strong communication skills and tailoring documents to different audiences. The fellow's program in the Physics Department will serve as a model for similar professional development resources applicable across the College of Science.