A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data

TL;DR

This paper measures the gravitational lensing effect of galaxy clusters on the CMB using SPT and DES data, achieving high significance detection and constraining the mass-richness relation.

Contribution

It provides the first high-significance measurement of CMB lensing by galaxy clusters using combined SPT and DES data, improving mass calibration methods.

Findings

Detected CMB lensing by galaxy clusters at 8.1σ significance.

Constrained the mass-richness relation to 17% precision.

Found good agreement with galaxy lensing constraints.

Abstract

Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. The cluster catalog used in this analysis contains 3697 members with mean redshift of $\bar{z} = 0.45$. We detect lensing of the CMB by the galaxy clusters at $8.1\sigma$ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly $17\%$ precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentering.