Collaborative Research: Taking Measure of the Universe with Galaxy and Cluster Surveys

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AST-0708490/AST-0708539Gonzalez/MohrThis project will execute a series of progressively more precise measurements of the expansion history of the Universe using galaxy cluster surveys and the clustering of galaxies. This team will complete and characterize two multi-band optical and infrared cluster surveys, the IRAC Shallow Cluster Survey (ISCS), using the Spitzer Space Telescope, and the Blanco Cosmology Survey (BCS), using the Blanco 4m telescope in Chile. The BCS will be used to measure the galaxy power spectrum with 3.5 million galaxies extending to redshifts greater than one. These new programs will be coordinated with current and forthcoming millimeter-wave surveys designed to find clusters using the Sunyaev-Zel'dovich effect. Future surveys intended to deliver constraints on the dark energy equation of state will invariably be limited by systematic rather than statistical uncertainties. The ISCS and BCS will clarify and quantify these systematic effects, while simultaneously obtaining new, near-term cosmological constraints. The work uses catalog and cluster simulations to estimate precisely the survey completeness and contamination, and the cluster mass estimate accuracy. It also focuses on fields with optical/infrared and mm-wave data, now or soon, and with some existing X-ray data. The multi-wavelength approach enables a cross-calibration of the leading cluster selection methods, the possibility of developing cleaner and more sensitive selection techniques, and direct tests of the selection models.This project will significantly impact larger experiments under way and to come. Because the BCS will constitute the largest contiguous deep optical survey in the southern hemisphere, the resulting public data set will be of great value for numerous other applications, such as galaxy evolution studies. This team has a record of working with K-12 teachers and students, and will expand that work in conjunction with the present research.