X-RAY PROPERTIES OF THE FIRST SUNYAEV-ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTER SAMPLE FROM THE SOUTH POLE TELESCOPE
Author(s)Andersson, Karl; Bautz, Marshall W.
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We present results of X-ray observations of a sample of 15 clusters selected via their imprint on the cosmic microwave background from the thermal Sunyaev-Zel'dovich (SZ) effect. These clusters are a subset of the first SZ-selected cluster catalog, obtained from observations of 178 deg[superscript 2] of sky surveyed by the South Pole Telescope (SPT). Using X-ray observations with Chandra and XMM-Newton, we estimate the temperature, T[subscript X], and mass, M[subscript g], of the intracluster medium within r [subscript 500] for each cluster. From these, we calculate Y[subscript X] = M[subscript g]T[subscript X] and estimate the total cluster mass using an M [subscript 500]-Y[subscript X] scaling relation measured from previous X-ray studies. The integrated Comptonization, Y [subscript SZ], is derived from the SZ measurements, using additional information from the X-ray-measured gas density profiles and a universal temperature profile. We calculate scaling relations between the X-ray and SZ observables and find results generally consistent with other measurements and the expectations from simple self-similar behavior. Specifically, we fit a Y [subscript SZ]-Y[subscript X] relation and find a normalization of 0.82 ± 0.07, marginally consistent with the predicted ratio of Y [subscript SZ]/Y[subscript X] = 0.91 ± 0.01 that would be expected from the density and temperature models used in this work. Using the Y[subscript X]-derived mass estimates, we fit a Y [subscript SZ]-M [subscript 500] relation and find a slope consistent with the self-similar expectation of Y [subscript SZ]∝M [superscript 5/3] with a normalization consistent with predictions from other X-ray studies. We find that the SZ mass estimates, derived from cosmological simulations of the SPT survey, are lower by a factor of 0.78 ± 0.06 relative to the X-ray mass estimates. This offset is at a level of 1.3σ when considering the ~15% systematic uncertainty for the simulation-based SZ masses. Overall, the X-ray measurements confirm that the scaling relations of the SZ-selected clusters are consistent with the properties of other X-ray-selected samples of massive clusters, even allowing for the broad redshift range (0.29 < z < 1.08) of the sample.
DepartmentKavli Institute for Astrophysics and Space Research
The Astrophysical Journal
Andersson, K., B. A. Benson, P. A. R. Ade, K. A. Aird, B. Armstrong, M. Bautz, L. E. Bleem, et al. “X-RAY PROPERTIES OF THE FIRST SUNYAEV-ZEL’DOVICH EFFECT SELECTED GALAXY CLUSTER SAMPLE FROM THE SOUTH POLE TELESCOPE.” The Astrophysical Journal 738, no. 1 (August 11, 2011): 48. © 2011 The American Astronomical Society
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