HIGH-REDSHIFT COOL-CORE GALAXY CLUSTERS DETECTED VIA THE SUNYAEV-ZEL'DOVICH EFFECT IN THE SOUTH POLE TELESCOPE SURVEY

• Main Authors: Bautz, Marshall W. (Contributor), McDonald, Michael A. (Contributor)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: Institute of Physics/American Astronomical Society, 2015-02-26T17:00:49Z.
• Subjects: Article
• Online Access: Get fulltext

We report the first investigation of cool-core properties of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect. We use 13 galaxy clusters uniformly selected from 178 deg[superscript 2] observed with the South Pole Telescope (SPT) and followed up by the Chandra X-ray Observatory. They form an approximately mass-limited sample (>3 × 10[superscript 14] M ☉ h[superscript -1][subscript 70]) spanning redshifts 0.3 < z < 1.1. Using previously published X-ray-selected cluster samples, we compare two proxies of cool-core strength: surface brightness concentration (c[subscript SB]) and cuspiness (α). We find that c[subscript SB] is better constrained. We measure c[subscript SB] for the SPT sample and find several new z > 0.5 cool-core clusters, including two strong cool cores. This rules out the hypothesis that there are no z > 0.5 clusters that qualify as strong cool cores at the 5.4σ level. The fraction of strong cool-core clusters in the SPT sample in this redshift regime is between 7% and 56% (95% confidence). Although the SPT selection function is significantly different from the X-ray samples, the high-z c [subscript SB] distribution for the SPT sample is statistically consistent with that of X-ray-selected samples at both low and high redshifts. The cool-core strength is inversely correlated with the offset between the brightest cluster galaxy and the X-ray centroid, providing evidence that the dynamical state affects the cool-core strength of the cluster. Larger SZ-selected samples will be crucial in understanding the evolution of cluster cool cores over cosmic time.
National Science Foundation (U.S.) (South Pole Telescope Program, grant ANT-0638937)
Germany. Bundesministerium für Bildung und Forschung (Excellence Initiative, EXC project No. 153)
Chandra X-ray Center (U.S.) (Chandra award No. GO2-13006A)
National Science Foundation (U.S.) (NSF Physics Frontier Center grant PHY-0114422)
Kavli Foundation
Gordon and Betty Moore Foundation
National Science Foundation (U.S.) (NSF grant AST-1009012)
National Science Foundation (U.S.) (SAO support, grant MRI-0723073)
National Science Foundation (U.S.) (SAO support, grant AST-1009649)
Natural Sciences and Engineering Research Council of Canada
Harvard-Smithsonian Center for Astrophysics (Clay Fellowship)
Kavli Institute for Cosmological Physics at the University of Chicago (KICP Fellowship)
Pennsylvania State University (contract 2834-MIT-SAO-4018 to the Massachusetts Institute of Technology) In
United States. National Aeronautics and Space Administration (NASA Hubble Fellowship grant HST-HF-51308.01)
Alfred P. Sloan Foundation (Research Fellowship)