OPTICAL REDSHIFT AND RICHNESS ESTIMATES FOR GALAXY CLUSTERS SELECTED WITH THE SUNYAEV-Zel'dovich EFFECT FROM 2008 SOUTH POLE TELESCOPE OBSERVATIONS
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States)
- Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States)
- Department of Physics and Astronomy, Cardiff University, CF24 3YB (United Kingdom)
- University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)
- Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
- National Center for Supercomputing Applications, University of Illinois, 1205 West Clark Street, Urbana, IL 61801 (United States)
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202 (United States)
- Department of Physics, University of California, Berkeley, CA 94720 (United States)
- Institut dAstrophysique de Paris, 98bis bd Arago, F-75014 Paris (France)
- Los Alamos National Laboratory, Los Alamos, New Mexico, NM 87545 (United States)
- Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
We present redshifts and optical richness properties of 21 galaxy clusters uniformly selected by their Sunyaev-Zel'dovich (SZ) signature. These clusters, plus an additional, unconfirmed candidate, were detected in a 178 deg{sup 2} area surveyed by the South Pole Telescope (SPT) in 2008. Using griz imaging from the Blanco Cosmology Survey and from pointed Magellan telescope observations, as well as spectroscopy using Magellan facilities, we confirm the existence of clustered red-sequence galaxies, report red-sequence photometric redshifts, present spectroscopic redshifts for a subsample, and derive R{sub 200} radii and M{sub 200} masses from optical richness. The clusters span redshifts from 0.15 to greater than 1, with a median redshift of 0.74; three clusters are estimated to be at z>1. Redshifts inferred from mean red-sequence colors exhibit 2% rms scatter in {sigma}{sub z}/(1 + z) with respect to the spectroscopic subsample for z < 1. We show that the M{sub 200} cluster masses derived from optical richness correlate with masses derived from SPT data and agree with previously derived scaling relations to within the uncertainties. Optical and infrared imaging is an efficient means of cluster identification and redshift estimation in large SZ surveys, and exploiting the same data for richness measurements, as we have done, will be useful for constraining cluster masses and radii for large samples in cosmological analysis.
- OSTI ID:
- 21471232
- Journal Information:
- Astrophysical Journal, Vol. 723, Issue 2; Other Information: DOI: 10.1088/0004-637X/723/2/1736; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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