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Optical Spectroscopy and Velocity Dispersions of Galaxy Clusters from the SPT-SZ Survey

Ruel, J. and Lueker, M. and Padin, S. and Shirokoff, E. and Vieira, J. D. (2014) Optical Spectroscopy and Velocity Dispersions of Galaxy Clusters from the SPT-SZ Survey. Astrophysical Journal, 792 (1). Art. No. 45. ISSN 0004-637X.

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We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 61 spectroscopic cluster redshifts, and 48 velocity dispersions each calculated with more than 15 member galaxies. This catalog also includes 19 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we find that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (≾30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a ~30% log-normal scatter in dispersion at fixed mass, and a ~10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.

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Additional Information:© 2014 American Astronomical Society. Received 2013 November 20; accepted 2014 July 10; published 2014 August 13. This paper includes spectroscopic data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile. Time was allocated through Harvard-CfA (PIs Bayliss, Brodwin, Foley, and Stubbs) and the Chilean National TAC (PI Clocchiatti). Gemini South access was obtained through NOAO. (PI Mohr, GS-2009B-Q-16, and PI Stubbs, GS-2011A-C-3 and GS-2011B-C-6). The VLT programs were granted through DDT (PI Carlstrom, 286.A-5021) and ESO (PI Bazin, 087.A-0843, and PI Chapman, 285.A-5034 and 088.A-0902). Optical imaging data from the Blanco 4 m at Cerro Tololo Interamerican Observatories (programs 2005B-0043, 2009B-0400, 2010A-0441, 2010B-0598) are included in this work. Additional imaging data were obtained with the 6.5 m Magellan Telescopes and the Swope telescope, which are located at the Las Campanas Observatory in Chile. This work is based in part on observations made with the Spitzer Space Telescope (PIDs 60099, 70053), which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. The South Pole Telescope program is supported by the National Science Foundation through grant ANT-0638937. Partial support is also provided by the NSF Physics Frontier Center grant PHY-0114422 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation, and the Gordon and Betty Moore Foundation. Galaxy cluster research at Harvard is supported by NSF grant AST-1009012. Galaxy cluster research at SAO is supported in part by NSF grants AST-1009649 and MRI-0723073. Support for X-ray analysis was provided by NASA through Chandra Award Nos. 12800071, 12800088, and 13800883 issued by the Chandra X-Ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA. The McGill group acknowledges funding from the National Sciences and Engineering Research Council of Canada, Canada Research Chairs program, and the Canadian Institute for Advanced Research. X-ray research at the CfA is supported through NASA Contract NAS 8-03060. The Munich group was supported by The Cluster of Excellence “Origin and Structure of the Universe,” funded by the Excellence Initiative of the Federal Government of Germany, EXC project number 153. R.J.F. is supported by a Clay Fellowship. B.A.B is supported by a KICP Fellowship, M.B. and M.M. acknowledge support from contract 2834-MIT-AO-4018 from the Pennsylvania State University to the Massachusetts Institute of Technology. M.D. acknowledges support from an Alfred P. Sloan Research Fellowship, W.F. and C.J. acknowledge support from the Smithsonian Institution. B.S. acknowledges support from the Brinson Foundation. A.C. received support from PFB-06 CATA, Chile. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Funding AgencyGrant Number
Kavli FoundationUNSPECIFIED
Gordon Betty Moore FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Research Chairs programUNSPECIFIED
Canadian Institute for Advanced Research (CIAR)UNSPECIFIED
NASANAS 8-03060
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Excellence Initiative of the Federal Government, GermanyUNSPECIFIED
Clay FellowshipUNSPECIFIED
Pennsylvania State University2834-MIT-AO-4018
Alfred P. Sloan FoundationUNSPECIFIED
Smithsonian InstitutionUNSPECIFIED
Brinson FoundationUNSPECIFIED
CATA, ChilePFB-06
Department of Energy (DOE)DE-AC02-05CH11231
Subject Keywords:catalogs; galaxies: clusters: general
Issue or Number:1
Record Number:CaltechAUTHORS:20140925-091539489
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Official Citation:Optical Spectroscopy and Velocity Dispersions of Galaxy Clusters from the SPT-SZ Survey J. Ruel et al. 2014 ApJ 792 45
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50023
Deposited By: Ruth Sustaita
Deposited On:25 Sep 2014 17:21
Last Modified:03 Oct 2019 07:19

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