THE YSZ–YX SCALING RELATION AS DETERMINED FROM PLANCK AND CHANDRA

Sunyaev–Zeldovich (SZ) clusters surveys, such as 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 (D2AYSZ/CYX) = −0.202 ± 0.024 at the pivot point CYX = 8 × 10−5 Mpc2. This corresponds to a YSZ/YX ratio of 0.82 ± 0.024, in good agreement with X-ray expectations after including the effects of gas clumping. The slope of the relation is α = 0.916 ± 0.032, consistent with unity at ≈2.3σ. We are unable to detect intrinsic scatter, and find no evidence that the scaling relation depends on cluster dynamical state.