Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 20, 2014 | Published
Journal Article Open

CLASH-X: A Comparison of Lensing and X-Ray Techniques for Measuring the Mass Profiles of Galaxy Clusters


We present profiles of temperature, gas mass, and hydrostatic mass estimated from new and archival X-ray observations of CLASH clusters. We compare measurements derived from XMM and Chandra observations with one another and compare both to gravitational lensing mass profiles derived with CLASH Hubble Space Telescope and Subaru Telescope lensing data. Radial profiles of Chandra and XMM measurements of electron density and enclosed gas mass are nearly identical, indicating that differences in hydrostatic masses inferred from X-ray observations arise from differences in gas-temperature measurements. Encouragingly, gas temperatures measured in clusters by XMM and Chandra are consistent with one another at ~100–200 kpc radii, but XMM temperatures systematically decline relative to Chandra temperatures at larger radii. The angular dependence of the discrepancy suggests that additional investigation on systematics such as the XMM point-spread function correction, vignetting, and off-axis responses is yet required. We present the CLASH-X mass-profile comparisons in the form of cosmology-independent and redshift-independent circular-velocity profiles. We argue that comparisons of circular-velocity profiles are the most robust way to assess mass bias. Ratios of Chandra hydrostatic equilibrium (HSE) mass profiles to CLASH lensing profiles show no obvious radial dependence in the 0.3–0.8 Mpc range. However, the mean mass biases inferred from the weak-lensing (WL) and SaWLens data are different. As an example, the weighted-mean value at 0.5 Mpc is 〈b〉 = 0.12 for the WL comparison and 〈b〉 = −0.11 for the SaWLens comparison. The ratios of XMM HSE mass profiles to CLASH lensing profiles show a pronounced radial dependence in the 0.3–1.0 Mpc range, with a weighted mean mass bias value rising to 〈b〉 gsim 0.3 at ~1 Mpc for the WL comparison and 〈b〉 ≈ 0.25 for the SaWLens comparison. The enclosed gas mass profiles from both Chandra and XMM rise to a value ≈1/8 times the total-mass profiles inferred from lensing at ≈0.5 Mpc and remain constant outside of that radius, suggesting that M_gas × 8 profiles may be an excellent proxy for total-mass profiles at ≳ 0.5 Mpc in massive galaxy clusters.

Additional Information

© 2014 The American Astronomical Society. Received 2014 June 2; accepted 2014 August 25; published 2014 October 1. M.D. and A.H. acknowledge the partial support of STScI/NASA award HST-GO-12065.07-A and NASA award NNX13AI41G. M.D. and G.M.V. benefitted from discussions of this work with Jim Bartlett. The Dark Cosmology Centre is funded by the DNRF. A.M. was partially supported through NASA ADAP award NNX12AE45G. S.E. acknowledges the financial contribution from contracts ASI-INAF I/023/05/0 and I/088/06/0. The work of L.A.M. and J.M. was carried out at Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. M.M. acknowledges financial contribution from the agreement ASI/INAF I/023/12/0 and from the project INFN PD51. Support for A.Z. is provided by NASA through aHubble Fellowship grant HST-HF-51334.01-A awarded by STScI. Facilities: CXO, XMM, HST

Attached Files

Published - 0004-637X_794_2_136.pdf


Files (1.6 MB)
Name Size Download all
1.6 MB Preview Download

Additional details

August 22, 2023
March 5, 2024