SPT-CL J0205-5829: A z = 1.32 Evolved Massive Galaxy Cluster in the South Pole Telescope Sunyaev-Zel'dovich Effect Survey
Gladders, M. D.; Rest, A.; Foley, R. J.; Zenteno, A.; Desai, S.; Bleem, L. E.; Stalder, B.; Stark, A. A.; Bayliss, M.; Stubbs, C. W.; George, E. M.; Reichardt, C. L.; Aird, K. A.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Holzapfel, W. L.; Hrubes, J. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Lueker, M.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mohr, J. J.; Montroy, T. E.; Padin, S.; Plagge, T.; Pryke, C.; Ruhl, J. E.; Schaffer, K. K.; Shaw, L.; Shirokoff, E.; Spieler, H. G.; Staniszewski, Z.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.; Vikhlinin, A.; Armstrong, R.; Ashby, M. L. N.; Saro, A.; McDonald, M.; Stanford, S. A.; Brodwin, M.; Forman, W. R.; Murray, S. S.; Gonzalez, A. H.; Marrone, D. P.; High, F. W.; Hoover, S.; Natoli, T.; Ruel, J.; Story, K.; Jones, C.; Song, J.; Clocchiatti, A.; Šuhada, R.; Sayre, J. T.; Mocanu, L.; Saliwanchik, B. R.; Liu, J.; Andersson, K.; Bautz, M.; Dudley, J. P.; Joy, M.; Cho, H. M.; Mantz, A.; Nurgaliev, D.; Bazin, G.; Gettings, D.
United States, Germany, Chile, Canada
Abstract
The galaxy cluster SPT-CL J0205-5829 currently has the highest spectroscopically confirmed redshift, z = 1.322, in the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. XMM-Newton observations measure a core-excluded temperature of TX = 8.7+1.0 -0.8 keV producing a mass estimate that is consistent with the Sunyaev-Zel'dovich-derived mass. The combined SZ and X-ray mass estimate of M 500 = (4.8 ± 0.8) × 1014 h -1 70 M ⊙ makes it the most massive known SZ-selected galaxy cluster at z > 1.2 and the second most massive at z > 1. Using optical and infrared observations, we find that the brightest galaxies in SPT-CL J0205-5829 are already well evolved by the time the universe was <5 Gyr old, with stellar population ages gsim3 Gyr, and low rates of star formation (<0.5 M ⊙ yr-1). We find that, despite the high redshift and mass, the existence of SPT-CL J0205-5829 is not surprising given a flat ΛCDM cosmology with Gaussian initial perturbations. The a priori chance of finding a cluster of similar rarity (or rarer) in a survey the size of the 2500 deg2 SPT-SZ survey is 69%.