JOINT ANALYSIS OF CLUSTER OBSERVATIONS. II. CHANDRA/XMM-NEWTON X-RAY AND WEAK LENSING SCALING RELATIONS FOR A SAMPLE OF 50 RICH CLUSTERS OF GALAXIES

By A. Mahdavi, H. Hoekstra, Arif Babul, C. Bildfell, Tesla E. Jeltema, J. Henry. 2012

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We present a study of multiwavelength X-ray and weak lensing scaling relations for a sample of 50 clusters of galaxies. Our analysis combines Chandra and XMM-Newton data using an energy-dependent cross-calibration. After considering a number of scaling relations, we find that gas mass is the most robust estimator of weak lensing mass, yielding 15% ± 6% intrinsic scatter at (the pseudo-pressure YX yields a consistent scatter of 22% ± 5%). The scatter does not change when measured within a fixed physical radius of 1 Mpc. Clusters with small brightest cluster galaxy (BCG) to X-ray peak offsets constitute a very regular population whose members have the same gas mass fractions and whose even smaller (<10%) deviations from regularity can be ascribed to line of sight geometrical effects alone. Cool-core clusters, while a somewhat different population, also show the same (<10%) scatter in the gas mass–lensing mass relation. There is a good correlation and a hint of bimodality in the plane defined by BCG offset and central entropy (or central cooling time). The pseudo-pressure YX does not discriminate between the more relaxed and less relaxed populations, making it perhaps the more even-handed mass proxy for surveys. Overall, hydrostatic masses underestimate weak lensing masses by 10% on the average at ; but cool-core clusters are consistent with no bias, while non-cool-core clusters have a large and constant 15%–20% bias between and , in agreement with N-body simulations incorporating unthermalized gas. For non-cool-core clusters, the bias correlates well with BCG ellipticity. We also examine centroid shift variance and power ratios to quantify substructure; these quantities do not correlate with residuals in the scaling relations. Individual clusters have for the most part forgotten the source of their departures from self-similarity.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/44073c161a30c180379157ed9ef96db1a52068c2

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Citations in the corpus

The Atacama Cosmology Telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data (2013, background): “For example, Mahdavi et al. (2013) find that hydrostatic masses are lower than weak lensing masses by about 10% atR500; Zhang et al. (2010) and Vikhlinin et al. (2009a) find reasonable agreement; while Planck Collaboration et al. (2013) find hydrostatic masses to be about 20% larger than weak…”
Weighing the Giants – III. Methods and measurements of accurate galaxy cluster weak-lensing masses (2012, background): “However, the authors adopt mass-apertur measurements for their multiwavelength comparisons in Hoekstra (2007); Mahdavi et al. (2008); Hoekstra et al. (2012); Mahdavi et al.(2013).”
GALAXY CLUSTER BARYON FRACTIONS REVISITED (2013, background): “Mahdavi et al. (2013) meanwhile find that, for their full sample, the X-ray masses are low by 12% relative to lensing, but with the cool-core systems having larger relative X-ray masses.”
redMaPPer. I. ALGORITHM AND SDSS DR8 CATALOG (2013, background): “We assume every galaxy cluster halo has a bright, dominant galaxy residing at its center (e.g., von der Linden et al. 2007, 2012; Menanteau et al. 2013; Mahdavi et al. 2012; Song et al. 2012b; Stott et al. 2012, see also paper II).”
Planck 2013 results. XX. Cosmology from Sunyaev-Zeldovich cluster counts (2013, background): “Most recent work points to relatively good agreement between X-ray and WL masses, with MHE/MWL ' 0.9 on average, and MHE/MWL ' 1 for relaxed systems (Mahdavi et al. 2013; von der Linden et al. 2014).”