Exploring the Stellar Content of the Galactic Halo

在过去的十年里，我们对银河系晕、遥远的银河系球状星团和银河系卫星星系中的恒星进行详细丰度分析的能力发生了一场革命，因为在当代大型望远镜和高效光谱仪出现之前，这些恒星太过微弱，无法进行高色散光谱分析。根据这一奖项，朱迪思·科恩博士（加州理工学院）将对银河系晕的化学演化进行详细的研究，利用这一巨大的技术进步，并利用她之前在美国国家科学基金会支持下的努力，在那里发现了大量金属含量极低的恒星样本。这些晕区恒星和球状星团中的元素丰度模式，对我们银河系的早期时代、银河系化学演化的开始、在早期时代产生许多元素的可能恒星来源（非常大质量的恒星和II型超新星）、银河系的年龄、晕区恒星和球状星团之间的关系有着直接的影响。以及星际介质和星系间介质的组成。这样的恒星提供了一个机会来研究代表高红移宇宙的当地物质的一般化学丰度。通过这项研究，我们将对银河系恒星晕和银河系周围的卫星星系之间的关系获得新的见解，无论是现在看到的还是遥远的过去。在这个奖项下，科恩博士还将继续致力于青年科学家的发展，特别是女性和少数民族，为本科生提供宝贵的研究经验。此外，面向公众和主要在本科院校举办的讲座将继续进行。科恩博士还将在加州理工学院的卡希尔天文学和天体物理学中心的大厅里举办一个面向公众的展览。

In the past decade there has been a revolution in our ability to carry out detailed abundance analyses of stars in the Galactic halo, distant Milky Way globular clusters, and the satellite galaxies of the Milky Way, because, prior to the current generation of large telescopes and efficient spectrographs, these stars were too faint for high dispersion spectroscopy. Under this award, Dr. Judith Cohen (California Institute of Technology) will carry out a study of the chemical evolution of the halo of the Milky Way galaxy in detail, taking advantage of this tremendous advance in technology as well as leveraging off her previous, NSF-supported efforts, in which large samples of extremely metal-poor stars were identified. The elemental abundance patterns in these halo stars, both in the field and in the globular clusters, have direct implications for the early epochs of our Galaxy, the onset of chemical evolution of the Galaxy, the possible stellar sources which produced many elements at very early epochs (very massive stars and Type II supernovae), the age of the Galaxy, the relationship between the halo field stars and the galactic globular clusters, and the composition of the interstellar medium and the intergalactic medium. Such stars provide a chance to study the general chemical abundances in local material representing the high redshift Universe. Through this research, new insight will be gained into the relationship between the Galactic stellar halo and the satellite galaxies around the Milky Way, both as seen now and in the distant past.Under this award Dr. Cohen will also continue to be dedicated to the development of young scientists, particularly women and minorities, by providing valuable research experiences for undergraduates. In addition, lectures, both for the general public and at primarily undergraduate institutions, will continue. Dr. Cohen also will produce an exhibit intended for the general public in the lobby of the Cahill Center for Astronomy and Astrophysics, located on the campus of Caltech.