NOAO >   Observing Info >   Approved Programs >   2009B-0339

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Proposal Information for 2009B-0339


PI: sara salimbeni, UMASS, salimben@astro.umass.edu
Address: Astronomy Department, 710 North Pleasant st, amherst, ma 01002, united States

Title: GOODS-South field: Large scale structure and forming clusters at z=2.3

Abstract: Using a 3D detection algorithm, based on high quality photometric redshifts, we identified 3 compact high density peaks, embedded in a larger scale overdensity of galaxies at z=2.3 in the GOODS-S field. The galaxies in these density peaks show significant mass and color segregation: the estimated masses for these structures are higher than 2-3 \cdot 10^14 M_\odot, suggesting that we might have discovered the most distant clusters of galaxies known to date. The few existing spectra are not sufficient to derive their basic properties. We therefore propose Multi-Object Spectroscopy of ~ 55 candidate members to determine the velocity distribution, dynamical status and total mass of the structures and study the properties of individual cluster galaxies. These early clusters might provide a bridge to understand the evolution from distant z=3-4 protoclusters and the well studied clusters at z~1-1.5 where are many of the properties of local systems already in place.


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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