利用来自 SPTpol 的极化数据探测宇宙微波背景（CMB）聚束效应。

Detection of CMB-Cluster Lensing using Polarization Data from SPTpol.

机构信息

Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.

School of Physics, University of Melbourne, Parkville VIC 3010, Australia.

出版信息

Phys Rev Lett. 2019 Nov 1;123(18):181301. doi: 10.1103/PhysRevLett.123.181301.

DOI:10.1103/PhysRevLett.123.181301

PMID:31763885

Abstract

We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500 deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

摘要

我们首次报道了仅利用宇宙微波背景（CMB）极化探测到的星系团引力透镜效应。该透镜信号是使用新的估计器从沿着局部测量的背景 CMB 极化梯度方向旋转以星系团为中心的 Stokes QU 地图切口形成的堆叠图像中提取透镜偶极子特征来获得的。使用来自暗能量调查（DES）第三年完整星系团目录中约 18000 个 richness λ≥10 的星系团的 SPTpol 500 平方度调查的数据，我们在 4.8σ 处检测到了透镜效应。所选择样本的平均堆叠质量被发现为（1.43±0.40）×10^{14}M_{⊙}，这与使用 DES 数据进行的基于光学弱透镜的估计以及使用 SPTpol 温度数据进行的基于 CMB-透镜的估计相符。这一测量是未来低噪声 CMB 调查（如 CMB-S4）中星系团宇宙学的关键的第一步，对于这些调查来说，CMB 极化将成为星系团透镜测量的主要手段。