Extragalactic Globular Clusters and Galaxy Formation

AST-0808099 BrodieGlobular星团是星系形成时期、组装机制和后续演化的强大探测器。这是因为球状星团的形成与银河系历史上恒星形成时期的联系，以及球状星团在很大程度上以未改变的明亮灯塔的形式存活下来，特别是在星系晕中。球状星团也是简单的恒星群体，因此更容易分析和理解。为了最大限度地利用球状星团的独特能力来澄清悬而未决的问题，包括暗物质的分布和早期类型星系的恒星形成历史，理论模型和观测之间必须有协同作用，特别是在低红移时，可以适当详细地研究星系。银河系考古学的这种方法最近在Local Group中得到了有益的应用，现在是时候将其扩展到几十兆秒的距离，从而扩展到更具代表性的宇宙横截面。这个项目将聚焦于两个关键领域：1)星系组装和暗物质的作用，即星系的积木如何以及何时结合；2)恒星群，即恒星如何以及何时在这些积木中形成？它涉及一项史无前例的系统调查，考察球状星系团系统的基本性质，以及它们与其宿主星系的关系，特别关注早期类型的星系。这是第一次在宇宙学背景下建设性地整合球状星团和星系研究。这项调查将结合使用一套世界上最强大的地面设备的创新观测？S，以及一个跨越广泛子学科的世界领先的研究人员团队。关于附近星系化学动力学性质的里程碑式的数据集在未来几年将在科学上取得丰硕成果。此外，与名为科学伙伴的全国性非营利组织的伙伴关系将极大地加强这项工作的影响。目前蓬勃而成功的专业和公共外展计划将继续下去，成功地将妇女、本科生和少数族裔纳入前沿研究的记录已得到证明。

AST-0808099BrodieGlobular star clusters are powerful probes of the formation epochs, assembly mechanisms, and subsequent evolution of galaxies. This is because of the association of globular cluster formation with star-forming episodes in a galaxy's history, and because globular clusters survive as largely unaltered bright beacons, particularly in galaxy halos. Globular clusters are also simple stellar populations, and thus more easily analyzed and understood. To exploit to its fullest the unique ability of globular clusters to clarify outstanding issues, including the distribution of dark matter and the star formation histories of early-type galaxies, there must be a synergy between theoretical models and observations, particularly at low redshift where galaxies may be studied in suitable detail. This approach of galactic archaeology has recently been gainfully applied in the Local Group, and it is timely to extend it to distances of dozens of megaparsecs, and thus to a more representative cross-section of the Universe. This project will focus on two key areas: 1) Galaxy assembly and the role of dark matter, that is, how and when do the building blocks of galaxies combine, and 2) Stellar populations, that is, how and when do stars form within these building blocks? It involves an unprecedented systematic survey of the fundamental properties of globular cluster systems, and how they relate to their host galaxies, with a particular focus on early-type galaxies. This is the first constructive integration of globular cluster and galaxy research in a cosmological context.This survey will couple innovative observations using a suite of the world?s most powerful ground-based facilities with a team of world-leading researchers spanning a wide range of sub-disciplines. The landmark dataset on the chemo-dynamical properties of nearby galaxies will be scientifically fruitful for years to come. In addition, partnership with a national, non-profit organization called Science Buddies will greatly enhance the impacts of this work. The current vigorous and successful program of professional and public outreach will continue, with a proven record of successfully including women, undergraduates, and minorities in forefront research.