Chemical Abundances and the Formation and Evolution of the Galactic Bulge

克里斯蒂安·约翰逊博士获得美国国家科学基金会天文学和天体物理学博士后奖学金，在加州大学洛杉矶分校开展研究和教育项目。约翰逊博士将大幅增加对银河系凸起的红巨星分支（RGB）恒星沿着小轴和离轴场的光谱观测数量。该计划将首次将化学丰度的测定扩展到约1000颗膨胀巨星样品中的轻奇z元素和重中子俘获元素。这些数据将与约翰逊博士的论文工作结果相结合，该论文是对半人马座Omega中约1000颗RGB恒星的综合化学分析，旨在深入了解两个独立的“球状”系统的化学演化，这些系统显示出显著的自富集迹象，但金属丰度范围接近1000倍。Johnson还将开发一个光谱合成网络工具，旨在帮助公众、非科学专业的本科生和高等本科生更容易地进行恒星丰度的工作。该网络工具旨在成为一个指导教程，允许学生和公众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成分。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.