The important role of evolution in the Planck $Y_{SZ}$-mass calibration

TL;DR

This paper revises the Planck $Y_{SZ}$-mass calibration by allowing data-driven evolution, revealing significant deviations from self-similar evolution assumptions and highlighting the impact on mass bias estimates.

Contribution

It introduces a data-driven approach to determine evolution in the $Y_{SZ}$-mass relation, challenging previous assumptions of self-similar evolution.

Findings

Evolution proportional to $E^{2.5 ext{±}0.4}$, inconsistent with $E^{2/3}$

Slope of $Y_{SZ}$-mass relation is $1.51 ext{±}0.07$, shallower than previous estimates

Non-self-similar evolution affects Planck mass bias analyses

Abstract

In light of the tension between cosmological parameters from Planck cosmic microwave background and galaxy clusters, we revised the Planck analysis of the $Y_{SZ}$-mass calibration to allow evolution to be determined by the data instead of being imposed as an external constraint. Our analysis uses the very same data and Malmquist bias corrections as used by the Planck team in order to emphasize that differences in the results come from differences in the assumptions. The evolution derived from 71 calibrating clusters, with $0.05<z<0.45$, is proportional to $E^{2.5\pm0.4}(z)$, so inconsistent with the self-similar evolution ($E^{2/3}$) assumed by previous analyses. When allowing for evolution, the slope of $Y_{SZ}$-mass relation turns out to be $1.51\pm0.07$, which is shallower by $4.8\sigma$ than the value derived when assuming self-similar evolution, introducing a mass-dependent bias. The non-self-similar evolution of $Y_{SZ}$ has to be accounted for in analyses aimed to establish the biases of Planck masses.