SPT-CL J0205-5829: A z = 1.32 EVOLVED MASSIVE GALAXY CLUSTER IN THE SOUTH POLE TELESCOPE SUNYAEV-ZEL'DOVICH EFFECT SURVEY

• Main Authors: Andersson, Karl (Contributor), Bautz, Marshall W. (Contributor), McDonald, Michael A. (Contributor)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2015-02-03T18:23:28Z.
• Subjects: Article
• Online Access: Get fulltext

 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 T[subscript X] = 8.7[+1.0 over -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 [subscript 500] = (4.8 ± 0.8) × 10[superscript 14] h[-1 over 70] M [subscript ☉] 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 [> over ~]3 Gyr, and low rates of star formation (<0.5 M [subscript ☉] yr[superscript -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 deg[superscript 2] SPT-SZ survey is 69%.