The Ysz--Yx Scaling Relation as Determined from Planck and Chandra

TL;DR

This study constrains the Ysz--Yx scaling relation using Planck SZ and Chandra X-ray data, providing key calibration parameters for galaxy cluster mass estimates, with results consistent with theoretical expectations.

Contribution

It presents the first detailed measurement of the Ysz--Yx scaling relation parameters using combined SZ and X-ray data, including amplitude, slope, and scatter.

Findings

Ysz/Yx ratio of 0.82±0.024 consistent with X-ray models

Slope of the relation is 0.916±0.032, close to unity

No significant intrinsic scatter detected

Abstract

SZ clusters surveys like Planck, the South Pole Telescope, and the Atacama Cosmology Telescope, will soon be publishing several hundred SZ-selected systems. The key ingredient required to transport the mass calibration from current X-ray selected cluster samples to these SZ systems is the Ysz--Yx scaling relation. We constrain the amplitude, slope, and scatter of the Ysz--Yx scaling relation using SZ data from Planck, and X-ray data from Chandra. We find a best fit amplitude of \ln (D_A^2\Ysz/CY_X) = -0.202 \pm 0.024 at the pivot point CY_X=8\times 10^{-5} Mpc^2. This corresponds to a Ysz/Yx-ratio of 0.82\pm 0.024, in good agreement with X-ray expectations after including the effects of gas clumping. The slope of the relation is \alpha=0.916\pm 0.032, consistent with unity at \approx 2.3\sigma. We are unable to detect intrinsic scatter, and find no evidence that the scaling relation depends on cluster dynamical state.