Extragalactic Globular Clusters and Galaxy Formation

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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.