2018/09/18 by Satoru Takakura, S. Takakura, Mario A. O. Aguilar-Faúndez +79 · 21 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric sciences #Cosmic microwave background #Environmental science #Geology #Meteorology #Optics #Physics #Polarization (electrochemistry) #Radio Astronomy Observations and Technology #Remote sensing #Sky #Superconducting and THz Device Technology #Telescope #astro-ph.CO #astro-ph.IM #physics.ao-ph
paper · pdf · doi:10.3847/1538-4357/aaf381
published in The Astrophysical Journal 870(2), 102 (IOP Publishing) · 14 pages, 12 figures, 1 table, Submitted to ApJ
arxiv created 2018/09/18 · openalex publication_date 2019/01/10 · arxiv updated 2019/01/23 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/04
Abstract The polarization of the atmosphere has been a long-standing concern for ground-based experiments targeting cosmic microwave background (CMB) polarization. Ice crystals in upper tropospheric clouds scatter thermal radiation from the ground and produce a horizontally polarized signal. We report a detailed analysis of the cloud signal using a ground-based CMB experiment, P olarbear , located at the Atacama desert in Chile and observing at 150 GHz. We observe horizontally polarized temporal increases of low-frequency fluctuations (“polarized bursts,” hereafter) of ≲0.1 K when clouds appear in a webcam monitoring the telescope and the sky. The hypothesis of no correlation between polarized bursts and clouds is rejected with >24 σ statistical significance using three years of data. We consider many other possibilities including instrumental and environmental effects, and find no reasons other than clouds that can explain the data better. We also discuss the impact of the cloud polarization on future ground-based CMB polarization experiments.