Optical Redshift and Richness Estimates for Galaxy Clusters Selected with the Sunyaev-Zel'dovich Effect from 2008 South Pole Telescope Observations
Abstract
We present redshifts and optical richness properties of 21 galaxy clusters uniformly selected by their Sunyaev-Zel'dovich signature. These clusters, plus an additional, unconfirmed candidate, were detected in a 178 square-degree area surveyed by the South Pole Telescope 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_200 radii and M_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_z/(1+z) with respect to the spectroscopic subsample for z < 1. We show that M_200 cluster masses derived from optical richness correlate with masses derived from South Pole Telescope 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 Sunyaev-Zel'dovich 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.
Keywords
Cite
@article{arxiv.1003.0005,
title = {Optical Redshift and Richness Estimates for Galaxy Clusters Selected with the Sunyaev-Zel'dovich Effect from 2008 South Pole Telescope Observations},
author = {F. W. High and B. Stalder and J. Song and P. A. R. Ade and K. A. Aird and S. S. Allam and R. Armstrong and W. A. Barkhouse and B. A. Benson and E. Bertin and S. Bhattacharya and L. E. Bleem and M. Brodwin and E. J. Buckley-Geer and J. E. Carlstrom and P. Challis and C. L. Chang and T. M. Crawford and A. T. Crites and T. de Haan and S. Desai and M. A. Dobbs and J. P. Dudley and R. J. Foley and E. M. George and M. Gladders and N. W. Halverson and M. Hamuy and S. M. Hansen and G. P. Holder and W. L. Holzapfel and J. D. Hrubes and M. Joy and R. Keisler and A. T. Lee and E. M. Leitch and H. Lin and Y. -T. Lin and A. Loehr and M. Lueker and D. Marrone and J. J. McMahon and J. Mehl and S. S. Meyer and J. J. Mohr and T. E. Montroy and N. Morell and C. -C. Ngeow and S. Padin and T. Plagge and C. Pryke and C. L. Reichardt and A. Rest and J. Ruel and J. E. Ruhl and K. K. Schaffer and L. Shaw and E. Shirokoff and R. C. Smith and H. G. Spieler and Z. Staniszewski and A. A. Stark and C. W. Stubbs and D. L. Tucker and K. Vanderlinde and J. D. Vieira and R. Williamson and W. M. Wood-Vasey and Y. Yang and O. Zahn and A. Zenteno},
journal= {arXiv preprint arXiv:1003.0005},
year = {2015}
}
Comments
Main body: 2 tables, 6 figures, 12 pages. Appendix: 22 full-color images, 11 pages. Submitted to ApJ