NOAO >   Observing Info >   Approved Programs >   2014A-0490

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Proposal Information for 2014A-0490


PI: Vandana Desai, IPAC, Caltech, desai@ipac.caltech.edu
Address: USA

CoI: Pascale Jablonka, Ecole Polytechnique Federale de Lausanne
CoI: Gregory Rudnick, University of Kansas
CoI: Dennis Just, University of Toronto
CoI: Alfonso Aragaon-Salamanca, University of Nottingham
CoI: Gabriella de Lucia, INAF - Osservatorio Astronomico
CoI: Rose Finn, Siena College
CoI: Bo Milvang-Jensen, Dark Cosmology Centre
CoI: Bianca Poggianti, INAF - Osservatorio Astronomico di Padova
CoI: Dennis Zaritsky, University of Arizona
CoI: Francois Rerat, Ecole Polytechnique Federale de Lausanne

Title: Large scale structures around typical clusters at intermediate redshift

Abstract: Galaxies in clusters differ systematically from those in the field at all redshifts. Starting at intermediate redshifts, cluster populations rapidly become even rounder, redder, and deader. To understand why, we are undertaking a multiwavelength imaging and spectroscopic program to trace intermediate-redshift galaxy properties (star formation, stellar mass, color, morphology) from cluster cores out through the infall regions to the field. Here we propose to obtain multi-object optical spectroscopy of high density regions revealed by photometric redshifts in the infall regions of two galaxy clusters with a complete suite of imaging data. We propose to obtain spectroscopic redshifts with the goals of unambiguously identifying cluster members and estimating group velocity dispersions. More accurate redshifts will also lead to improved rest-frame colors for determining star formation rates, stellar masses, and passive fractions. These measurements will allow us to explore galaxy properties as functions of clustercentric distance, cluster velocity dispersion, group velocity dispersion, and local density. The observed trends will be used to pinpoint any environments that drive galaxy transformations, and will provide a benchmark for numerical simulations and semi-analytic models of cluster formation.


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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