Relation between X-ray and Sunyaev—Zeldovich Galaxy Cluster Mass Measurements

Abstract

We investigate the possibility of transferring the galaxy cluster mass scale calibrations from weak-lensing measurements to X-ray cluster mass measurements using Planck cluster mass measurements. For this purpose, we compare the mass measurements for 47 galaxy clusters that simultaneously enter the X-ray sample of clusters from Vikhlinin et al. (2009a, 2009b) and the sample of galaxy clusters from the second Planck catalogue of Sunyaev-Zeldovich sources. We show that except for a few outliers in the measurements, most of which arise from cluster projection effects in the Planck data, the scatter in the mass ratio turns out to be small, ~15%, while the accuracy of determining the mean mass ratio for this sample is about 2%. This allows the existing cluster mass measurement calibrations in the Planck survey to be transferred to Chandra X-ray mass measurements almost without any loss of accuracy. Using the derived relations and based on new cluster mass scale calibrations from weak-lensing measurements in clusters, we have obtained corrections to the constraints on cosmological parameters from Vikhlinin et al. (2009b). Given these corrections, σ₈ increases approximately by 4%, within one standard deviation of the uncertainty in the constraint on this quantity at constant Ω_m. We show that, given the systematic uncertainties, all of the currently available galaxy cluster mass function measurements yield approximately identical constraints on the parameters σ₈ and Ω_m.