NOAO >   Observing Info >   Approved Programs >   2007A-0509

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Proposal Information for 2007A-0509


PI: Anthony H. Gonzalez, University of Florida, anthony@astro.ufl.edu
Address: Astronomy Department, Bryant Space Science Center, PO Box 112055, Gainesville, FL 32611-2055, USA

CoI: Daniel Stern, JPL/Caltech
CoI: Mark Brodwin, JPL
CoI: S. Adam Stanford, IGPP/LLNL, UC Davis
CoI: Peter Eisenhardt, JPL
CoI: Arjun Dey, NOAO
CoI: Joseph J. Mohr, UIUC
CoI: Jeeseon Song, UIUC

Title: Galaxy Cluster Velocity Dispersions For Clusters in the IRAC Shallow Survey

Abstract: We plan to use the MARS spectrograph on the KPNO 4m to obtain velocity dispersions for 27 galaxy clusters at 0.4<z<1.2. These clusters are drawn from the IRAC Shallow Cluster Survey in the NDWFS Bootes region, which provides the first statistical sample of galaxy clusters (~ 300) spanning the entire redshift range 0<z<1.5. These observations, when combined with other data sets, will provide us with velocity dispersions for the 50 highest significance cluster detections in the survey, including a complete sample of clusters with M\ga10^14 M_\odot over the full redshift range and a less complete sample probing to lower mass. Dispersions or an equivalent mass estimator are a necessary prerequisite for studying evolution of the cluster galaxy population, so these observations are essential if we are to extract full value from our cluster sample. In parallel with this effort, we are creating mock cluster catalogs drawn from N-body simulations so that we can quantify in detail the distribution of cluster masses expected for the observed distribution of velocity dispersions. The resulting spectra will also be used to probe the stellar populations of massive cluster galaxies as a function of redshift and cluster mass.


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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