Collaborative Research: Structure and Evolution of M31's Stellar Halo from a Large-Scale Spectroscopic Survey

提案编号：AST-0307966 PI：Puragra Guhathakurta机构：加州大学，圣克鲁斯==（AST-0307966），包括加州大学洛杉矶分校的迈克尔·里奇（AST-0307931），弗吉尼亚大学的史蒂文·马博斯基（AST-0307842）和卫斯理大学的凯瑟琳约翰斯顿（AST-0307846）。这个合作者团队将通过进行一个大型的-规模光谱测量将产生恒星径向速度和金属丰度。 较大的样本将使他们能够通过确定平均金属丰度分布函数、外旋转曲线和晕的速度色散，在很宽的银河系中心距离范围内探索晕/外盘恒星群。 他们的研究将集中在最近从宽视场成像调查中发现的晕中离散物质流中的恒星的结果。 最终，他们的样本应该使他们能够评估M31吸积的卫星星系的破坏在多大程度上有助于形成晕群。 所有的合作者都涉及本科生和研究生的研究工作。 他们希望公开讲座，并在K-12教室谈论他们的研究，并使他们的工作成果向公众开放。 他们还计划购买一个窄带滤光片，用于Ca红外三重态的研究，这将提供给凯克望远镜的所有用户。

PROPOSAL NO: AST-0307966PI: Puragra GuhathakurtaINSTITUTION: University of California, Santa Cruz================================================================This collaborative project is led by Puragra Guhathakurta of UCSC (AST-0307966), and includes Michael Rich of UCLA (AST-0307931), Steven Majewski of University of Virginia (AST-0307842) and Kathryn Johnston of Wesleyan University (AST-0307846).This team of collaborators will improve our understanding of the nature and origin of the halo of M31 by carrying out a large-scale spectroscopic survey that will yield both stellar radial velocities and metallicities. The larger sample will allow them to explore the halo/outer disk stellar population over a wide range of galactocentric distances by determining the mean metallicity distribution function, the outer rotation curve, and the velocity dispersion of the halo. Their study will focus on results for stars in the discrete streams of material in the halo that have been discovered recently from wide field imaging surveys. Ultimately, their sample should allow them to assess the extent to which the disruption of satellite galaxies accreted by M31 has contributed to the formation of the halo population. All of the collaborators involve undergraduate and graduate students in their research efforts. They expect to give public lectures and to speak in K-12 classrooms about their research and to make the results of their work accessible to the public. They also plan to purchase a narrow band filter for work on the Ca infrared triplet, which will be made available to all users of the Keck telescopes.