Integrated Light Spectra of Globular Clusters: A New Frontier in Chemical Abundance Studies

Janet Colucci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，在加州大学圣克鲁斯分校（UCSC）开展研究和教育项目。星系最初是如何形成的，以及它们在整个生命周期中是如何变化的，这是天体物理学中最不为人所知的问题之一。许多项目都以解开这些谜团为中心。在这个项目中，他将通过从星团的综合光谱中获得20多种单独化学元素的化学丰度，来研究本星系群以外星系的详细化学演化。这名研究员的技术可以在1300万光年远的星系中测量化学丰度，而以前只能在50万光年内的星系中测量，即我们自己的银河系及其附近的卫星星系。连接恒星天文学和星系外天文学领域，这项技术将允许在所有星系类型的星系中组装大量详细的化学丰度样本，它将为重新考虑星系形成中的一系列经典问题提供基础。具体来说，这位研究员将测量大约40个球状星团的化学丰度，这些球状星团分别位于最近的大质量早期型（E/S0）星系NGC 5128和爆发恒星的M82星系中，她将把这些样本添加到她之前在M31、大麦哲伦星云和银河系的工作中，以解决星系和球状星团形成的问题。对这一范围的详细化学分析——与对银河系本地恒星的标准光学丰度分析相当——从未对早期型星系或星暴星系进行过分析。这个项目更广泛的影响包括一个重要的教育组成部分。该研究员将承担一项教育外展计划，重点是将天文学外展计划引入代表性不足的群体。在UCSC的“拓展视野”（EYH）项目中，这位研究员将为圣克鲁斯和蒙特利县的高中女生团体开发和展示实践天文学讲习班。EYH的目标是鼓励年轻女性在接受教育的早期参与科学、技术、工程和数学（STEM）领域，使她们能够追求STEM职业。这项努力的一个重要部分是为从事STEM职业的女性提供榜样和导师。该研究员还将通过UCSC的EYH组织旅行研讨会，将天文学和其他STEM领域带到服务不足的社区，从而扩大外联工作。她将建立一个基础设施，以促进UCSC天文系与EYH以及其他stem领域部门的持续参与。

Dr. Janet Colucci is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of California, Santa Cruz (UCSC). Precisely how galaxies initially form and how they change throughout their lifetimes are among the least understood problems in astrophysics. Many projects are centered on unraveling these mysteries. In this project the fellow will study the detailed chemical evolution of galaxies beyond the Local Group by obtaining chemical abundances of over 20 individual chemical elements from integrated light spectra of star clusters. The fellow's technique enables chemical abundance measurements in galaxies as distant as 13 million light-years that were previously only possible in galaxies within a half million light-years distance, i.e., our own Milky Way Galaxy and its nearby satellite galaxies. Bridging the fields of stellar astronomy and extragalactic astronomy, this technique will allow the assembly of a large sample of detailed chemical abundances in galaxies across all galaxy types, and it will provide the basis for reconsideration of a wide range of classic questions in galaxy formation.Specifically, the fellow will measure chemical abundances in a total sample of about 40 globular clusters residing in both the nearest massive early-type (E/S0) galaxy, NGC 5128, and in the starbursting M82 galaxy, which she will add to her previous work in M31, the Large Magellanic Cloud, and the Milky Way, to address galaxy and globular cluster formation questions. Detailed chemical analyses of this scope---comparable to standard optical abundance analyses of local Milky Way stars---have never been performed before for either an early-type or a starburst galaxy. The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach that focuses on bringing astronomy outreach programs to underrepresented groups. With the Expanding Your Horizons (EYH) program at UCSC, the fellow will develop and present hands-on astronomy workshops to groups of high school girls in Santa Cruz and Monterey counties. The goal of EYH is to encourage young women to engage in science, technology, engineering, and mathematics (STEM) fields early in their education to enable their pursuit of STEM careers. An important part of this endeavor is to provide female role models and mentors who are in STEM careers. The fellow will also expand outreach efforts through EYH at UCSC by organizing traveling workshops to bring astronomy and other STEM fields to underserved communities. She will establish an infrastructure to facilitate continuing involvement of the UCSC Astronomy Department with EYH as well as other STEM-field departments.