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The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters

McDonald, M. and Crites, A. T. and Lueker, M. and Padin, S. and Shirokoff, E. and Staniszewski, Z. and Vieira, J. D. and Williamson, R. (2014) The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters. Astrophysical Journal, 794 (1). Art. No. 67. ISSN 0004-637X.

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We present the results of an X-ray analysis of 80 galaxy clusters selected in the 2500 deg^2 South Pole Telescope survey and observed with the Chandra X-ray Observatory. We divide the full sample into subsamples of ~20 clusters based on redshift and central density, performing a joint X-ray spectral fit to all clusters in a subsample simultaneously, assuming self-similarity of the temperature profile. This approach allows us to constrain the shape of the temperature profile over 0 < r < 1.5R_(500), which would be impossible on a per-cluster basis, since the observations of individual clusters have, on average, 2000 X-ray counts. The results presented here represent the first constraints on the evolution of the average temperature profile from z = 0 to z = 1.2. We find that high-z (0.6 < z < 1.2) clusters are slightly (~30%) cooler both in the inner (r < 0.1R_(500)) and outer (r > R_(500)) regions than their low-z (0.3 < z < 0.6) counterparts. Combining the average temperature profile with measured gas density profiles from our earlier work, we infer the average pressure and entropy profiles for each subsample. Confirming earlier results from this data set, we find an absence of strong cool cores at high z, manifested in this analysis as a significantly lower observed pressure in the central 0.1R_(500) of the high-z cool-core subset of clusters compared to the low-z cool-core subset. Overall, our observed pressure profiles agree well with earlier lower-redshift measurements, suggesting minimal redshift evolution in the pressure profile outside of the core. We find no measurable redshift evolution in the entropy profile at r ≲ 0.7R_(500)—this may reflect a long-standing balance between cooling and feedback over long timescales and large physical scales. We observe a slight flattening of the entropy profile at r gsim R_(500) in our high-z subsample. This flattening is consistent with a temperature bias due to the enhanced (~3×) rate at which group-mass (~2 keV) halos, which would go undetected at our survey depth, are accreting onto the cluster at z ~ 1. This work demonstrates a powerful method for inferring spatially resolved cluster properties in the case where individual cluster signal-to-noise is low, but the number of observed clusters is high.

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McDonald, M.0000-0001-5226-8349
Additional Information:© 2014 The American Astronomical Society. Received 2014 April 24; accepted 2014 August 15; published 2014 September 24. We thank M. Voit and N. Battaglia for helpful discussions, along with K. Dolag, for sharing their simulated galaxy cluster pressure profiles. M. M. acknowledges support by NASA through a Hubble Fellowship grant HST-HF51308.01-A awarded by the Space Telescope Science Institute, which is operated by the Association ofUniversities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. The South Pole Telescope program is supported by the National Science Foundation through grants ANT-0638937 and PLR-1248097. 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. Support for X-ray analysis was provided by NASA through Chandra Award Numbers 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. Galaxy cluster research at Harvard is supported by NSF grant AST-1009012 and at SAO 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 forAdvanced Research. Argonne National Laboratory’s work was supported under U.S. Department of Energy contract DE-AC02-06CH11357. J.H.L. is supported by NASA through the Einstein Fellowship Program, grant number PF2-130094.
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF51308.01-A
Kavli FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
NASA Chandra Award12800071
NASA Chandra Award12800088
NASA Chandra Award13800883
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Research Chairs programUNSPECIFIED
Canadian Institute for Advanced Research (CIAR)UNSPECIFIED
Department of Energy (DOE)DE-AC02-06CH11357
Subject Keywords:galaxies: clusters: general; galaxies: clusters: intracluster medium; early universe; X-rays: galaxies: clusters
Issue or Number:1
Record Number:CaltechAUTHORS:20141107-142519525
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Official Citation:The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters M. McDonald et al. 2014 ApJ 794 67
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51458
Deposited By: Jason Perez
Deposited On:08 Nov 2014 00:10
Last Modified:09 Mar 2020 13:19

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