Title: A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data,
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.