Chemical Abundances and the Formation and Evolution of the Galactic Bulge

Christian约翰逊博士被授予NSF天文学和天体物理学博士后奖学金，在洛杉矶的加州大学开展研究和教育计划。约翰逊博士将在短轴和离轴磁场的沿着方向上，大幅增加对银河核球中红巨星分支（RGB）恒星的光谱观测数量。该计划将首次将化学丰度的测定扩展到约1，000颗球巨星样本中的轻奇Z元素和重中子捕获元素。这些数据将与约翰逊博士的论文工作的结果相结合，这是对半人马座欧米茄中约1,000颗RGB恒星的全面化学分析，以深入了解两个独立的“球状”系统的化学演化，这些系统表现出显着的自我富集迹象，但金属量范围几乎是1的一个因素，000.约翰逊博士还将开发一个光谱合成网络工具，旨在帮助使恒星丰度工作更容易为普通公众、本科非理科专业和高年级本科生所用。该网络工具旨在成为一个指导教程，使学生和公众能够在学习恒星演化和核合成的背景下积极参与确定恒星的化学组成。约翰逊博士将开发与网络工具相关的活动，这些活动适用于非科学专业和高级本科课程。

Dr. Christian Johnson is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of California, Los Angeles. Dr. Johnson will increase dramatically the number of spectroscopic observations of red giant branch (RGB) stars in the Galactic bulge along both minor axis and off-axis fields. This program will for the first time extend the determination of chemical abundances to light odd-Z elements and heavy neutron-capture elements in a sample of ~1,000 bulge giants. These data will be combined with the results of Dr. Johnson's dissertation work, a comprehensive chemical analysis of ~1,000 RGB stars in Omega Centauri, to provide insight into the chemical evolution of two independent "spheroidal" systems exhibiting signs of significant self-enrichment but that span a metallicity range of nearly a factor of 1,000.Dr. Johnson will also develop a spectrum synthesis webtool designed to help make stellar abundance work more accessible to the general public, undergraduate non-science majors, and advanced undergraduates. The webtool is intended to be a guided tutorial that allows students and the general public to actively participate in determining the chemical composition of stars in the context of learning about stellar evolution and nucleosynthesis. Dr. Johnson will develop activities associated with the webtool that are appropriate for use in both non-science major and advanced undergraduate classes.