NOAO >   Observing Info >   Approved Programs >   2006A-0563

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Proposal Information for 2006A-0563


PI: Mark Brodwin, JPL, mark.brodwin@jpl.nasa.gov
Address: 4800 Oak Grove Drive, M/S 169--506, Pasadena, CA 91109, USA

CoI: Michael Brown, Princeton
CoI: Arjun Dey, NOAO
CoI: Peter Eisenhardt, JPL
CoI: Anthony Gonzalez, University of Florida
CoI: Buell Jannuzi, NOAO
CoI: Daniel Stern, JPL

Title: Spectroscopy of three 1< z <2 Galaxy Cluster Candidates

Abstract: Massive galaxy clusters between 1 < z < 2 are a powerful probe of the evolution of large scale structure as well as the underlying cosmology. The \it Spitzer/IRAC Shallow survey is a 9 deg^2 mid-IR imaging survey in Bootes designed to detect galaxy clusters uniformly over this key redshift range. Complementary data includes the NDWFS and FLAMEX surveys, two large survey programs conducted using NOAO facilities. Using accurate photometric redshifts constructed from these data, we have identified over 20 robust high redshift (z > 1) cluster candidates. Seven of these are the targets of an HST/ACS program to search for Type Ia SNe, and to date 4 have been confirmed at 1.11< z < 1.41, including the most distant found in a cluster survey. We propose spectroscopic observations to confirm the remaining 3 clusters, including one at z~1.6 which would be the most distant cluster yet. This will allow a characterization of the early, massive stellar population and its star formation history, the ``downsizing'' phenomenon, and constrain the importance of dry merging in producing it. The HST program targets these relatively dust-free cluster host galaxies as they permit a much improved measurement of the equation of state of the dark energy.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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