Sunyaev-Zel'dovich Cluster Profiles Measured with the South Pole Telescope

TL;DR

This paper presents measurements of the Sunyaev-Zel'dovich effect in 15 galaxy clusters using the South Pole Telescope, analyzing their profiles and scaling relations to improve understanding of cluster properties.

Contribution

First detailed SZ profiles of galaxy clusters from SPT data are modeled and compared to X-ray estimates, confirming consistency with previous models and establishing tight scaling relations.

Findings

SZ profiles fit well with beta and NFW models

Y_SZ correlates strongly with Y_X and gas mass

Profiles are consistent with previous studies

Abstract

We present Sunyaev-Zel'dovich measurements of 15 massive X-ray selected galaxy clusters obtained with the South Pole Telescope. The Sunyaev-Zel'dovich (SZ) cluster signals are measured at 150 GHz, and concurrent 220 GHz data are used to reduce astrophysical contamination. Radial profiles are computed using a technique that takes into account the effects of the beams and filtering. In several clusters, significant SZ decrements are detected out to a substantial fraction of the virial radius. The profiles are fit to the beta model and to a generalized NFW pressure profile, and are scaled and stacked to probe their average behavior. We find model parameters that are consistent with previous studies: beta=0.86 and r_core/r_500 = 0.20 for the beta model, and (alpha, beta, gamma, c_500)=(1.0,5.5,0.5,1.0) for the generalized NFW model. Both models fit the SPT data comparably well, and both are consistent with the average SZ profile out to the virial radius. The integrated Compton-y parameter Y_SZ is computed for each cluster using both model-dependent and model-independent techniques, and the results are compared to X-ray estimates of cluster parameters. We find that Y_SZ scales with Y_X and gas mass with low scatter. Since these observables have been found to scale with total mass, our results point to a tight mass-observable relation for the SPT cluster survey.