Combining Planck and SPT Cluster Catalogs: Cosmological Analysis and Impact on the Planck Scaling Relation Calibration

Abstract

We provide the first combined cosmological analysis of South Pole Telescope (SPT) and Planck cluster catalogs. The aim is to provide an independent calibration for Planck scaling relations, exploiting the cosmological constraining power of the SPT-SZ cluster catalog and its dedicated weak lensing (WL) and X-ray follow-up observations. We build a new version of the Planck cluster likelihood. In the νΛCDM scenario, focusing on the mass slope and mass bias of Planck scaling relations, we find α_(SZ) = 1.49^(+0.07)_(−0.10) and (1−b)_(SZ) = 0.69^(+0.07)_(−0.14) respectively. The results for the mass slope show a ∼4σ departure from the self-similar evolution, α_(SZ) ∼1.8. This shift is mainly driven by the matter density value preferred by SPT data, Ω_m = 0.30 ± 0.03, lower than the one obtained by Planck data alone, Ω_m = 0.37^(+0.02)_(−0.06). The mass bias constraints are consistent both with outcomes of hydrodynamical simulations and external WL calibrations, (1−b) ∼ 0.8, and with results required by the Planck cosmic microwave background cosmology, (1−b) ∼ 0.6. From this analysis, we obtain a new catalog of Planck cluster masses M₅₀₀. We estimate the relation between the published Planck derived M_(SZ) masses and our derived masses, as a "measured mass bias," (1-b)_M. We analyze the mass, redshift, and detection noise dependence of (1-b)_M, finding an increasing trend toward high redshift and low mass. These results mimic the effect of departure from self-similarity in cluster evolution, showing different dependencies for the low-mass, high-mass, low-z, and high-z regimes.

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