The Sunyaev-Zeldovich Signal of the maxBCG SDSS Galaxy Clusters in WMAP

TL;DR

This study uses WMAP data to independently measure the Sunyaev-Zel'dovich effect in maxBCG galaxy clusters, confirming the discrepancy with theoretical expectations and supporting the idea that the tension is due to modeling rather than data issues.

Contribution

It provides an independent WMAP-based measurement of the SZ signal in maxBCG clusters, confirming the Planck results and highlighting the need to revise theoretical models.

Findings

WMAP detection consistent with Planck measurements

Discrepancy with theoretical expectations confirmed

Supports the hypothesis of a theoretical origin for the tension

Abstract

The Planck Collaboration measured the Sunyaev-Zel'dovich (SZ) decrement of optically selected clusters from the Sloan Digital Sky Survey, finding that it falls significantly below expectations based on existing mass calibration of the maxBCG galaxy clusters. Resolving this tension requires either the data to go up, or the theoretical expectations to come down. Here, we use data from the Wilkinson Microwave Anisotropy Probe (WMAP) to perform an independent estimate of the SZ decrement of maxBCG clusters. The recovered signal is consistent with that obtained using Planck, though with larger error bars due to WMAP's larger beam size and smaller frequency range. Nevertheless, this detection serves as an independent confirmation of the magnitude of the effect, and demonstrates that the observed discrepancy must be theoretical in origin.