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Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1

Foley, R. J. and Padin, S. and Vieira, J. D. (2011) Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1. Astrophysical Journal, 731 (2). Art. No. 86. ISSN 0004-637X.

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Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132^(+0.002)_(–0.003). Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of T_X = 11.0^(+2.6)_(–1.9) keV and a luminosity (within r _(500)) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 10_(44) erg s^(–1). The combined mass estimate from measurements of the SZ effect and X-ray data is M_(200) = (1.27 ± 0.21) × 10^(15) h ^(–1) _(70) M_⊙. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg^2 SPT survey region and that only one such galaxy cluster is expected in the entire sky.

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Additional Information:© 2011 American Astronomical Society. Received 2011 January 6; accepted 2011 February 4; published 2011 March 28. 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. This work is based in part on observations obtained with the Spitzer Space Telescope (PID 60099), 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. Additional data were obtained with the 6.5 m Magellan Telescopes located at the Las Campanas Observatory, Chile. Support for X-ray analysis was provided by NASA through Chandra Project Numbers 12800071 and 12800088 issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. Observations from VLT programs 086.A-0741 and 286.A-5021 were included in this work. We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA). Support for LAMBDA is provided by the NASA Office of Space Science. 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. 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 acknowledges support from the Excellence Cluster Universe and the DFG research program TR33. R.J.F. is supported by a Clay Fellowship. B.A.B. is supported by a KICP Fellowship, support for M. Brodwin was provided by the W. M. Keck Foundation, M. Bautz acknowledges support from contract 2834-MIT-SAO-4018 from the Pennsylvania State University to the Massachusetts Institute of Technology. A.C. acknowledges the support of grants Basal CATA PFB 06/09 and FONDAP No. 15010003. M.D. acknowledges support from an Alfred P. Sloan Research Fellowship, W.F. and C.J. acknowledge support from the Smithsonian Institution, and B.S. acknowledges support from the Brinson Foundation. Facilities: Blanco (NEWFIRM), CXO (ACIS), Magellan: Baade (IMACS), Magellan:Clay (LDSS3), Spitzer (IRAC), SPT, VLT:Antu (FORS2)
Funding AgencyGrant Number
NSF Physics Frontier CenterPHY-0114422
Kavli FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Chandra X-ray ObservatoryUNSPECIFIED
NASA Office of Space ScienceUNSPECIFIED
National Sciences and Engineering Research Council of CanadaUNSPECIFIED
Canada Research Chairs programUNSPECIFIED
Canadian Institute for Advanced ResearchUNSPECIFIED
NASANAS 8-03060
Excellence Cluster UniverseUNSPECIFIED
DFG research programUNSPECIFIED
Clay FellowshipUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Pennsylvania State University2834-MIT-SAO-4018
Alfred P. Sloan Research FellowshipUNSPECIFIED
Smithsonian InstitutionUNSPECIFIED
Brinson FoundationUNSPECIFIED
Subject Keywords:early universe; galaxies: clusters: individual (SPT-CL J2106-5844); galaxies: evolution; galaxies: formation; large-scale structure of universe
Issue or Number:2
Classification Code:PACS: 98.65.Cw; 95.85.Kr; 98.70.Qy; 98.62.Py; 98.80.Cq; 98.62.Qz
Record Number:CaltechAUTHORS:20110519-085350093
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Official Citation:Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1 R. J. Foley, K. Andersson, G. Bazin, T. de Haan, J. Ruel, P. A. R. Ade, K. A. Aird, R. Armstrong, M. L. N. Ashby, M. Bautz, B. A. Benson, L. E. Bleem, M. Bonamente, M. Brodwin, J. E. Carlstrom, C. L. Chang, A. Clocchiatti, T. M. Crawford, A. T. Crites, S. Desai, M. A. Dobbs, J. P. Dudley, G. G. Fazio, W. R. Forman, G. Garmire, E. M. George, M. D. Gladders, A. H. Gonzalez, N. W. Halverson, F. W. High, G. P. Holder, W. L. Holzapfel, S. Hoover, J. D. Hrubes, C. Jones, M. Joy, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch, M. Lueker, D. Luong-Van, D. P. Marrone, J. J. McMahon, J. Mehl, S. S. Meyer, J. J. Mohr, T. E. Montroy, S. S. Murray, S. Padin, T. Plagge, C. Pryke, C. L. Reichardt, A. Rest, J. E. Ruhl, B. R. Saliwanchik, A. Saro, K. K. Schaffer, L. Shaw, E. Shirokoff, J. Song, H. G. Spieler, B. Stalder, S. A. Stanford, Z. Staniszewski, A. A. Stark, K. Story, C. W. Stubbs, K. Vanderlinde, J. D. Vieira, A. Vikhlinin, R. Williamson and A. Zenteno doi: 10.1088/0004-637X/731/2/86
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:23724
Deposited By: Ruth Sustaita
Deposited On:19 May 2011 17:15
Last Modified:03 Oct 2019 02:49

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