SPT-3G: Measurement and Mitigation of mm-wave Polarized Atmospheric Emission
ORAL
Abstract
Ground-based detection of inflationary B-mode polarization with cosmic microwave background (CMB) experiments requires a detailed understanding of contaminating signals. B-mode power spectrum forecasts and simulations generally assume the atmosphere to be unpolarized, but this is not always the case. Polarized atmospheric emission has previously been reported by both the CLASS and POLARBEAR experiments in the Atacama Desert in Chile. This polarized radiation is thought to arise from a population of horizontally aligned ice crystals in the atmosphere, which scatter thermal radiation from the ground and contribute thermal emission. This creates a time-varying, anisotropic, horizontally polarized signal that is most prevalent at the large angular scales relevant to inflationary B-modes (> 0.5 degrees). I will present the first detection of polarized atmospheric emission at the South Pole using the South Pole Telescope (SPT) and offer a complete theoretical description of the effect, as well as present a full measured amplitude distribution of the signal from four years of SPT-3G Austral winter data. I will conclude with mitigation strategies and the relevance of this model to CMB experiment design and forecasting.
*The South Pole Telescope program is supported by the National Science Foundation (NSF) Office of Polar Programs and the U.S. Department of Energy's Office of Science High Energy Physics. Additional support was provided by the National Science Foundation Graduate Research Fellowship Program, the NASA Hubble Fellowship, and the JSPS Overseas Research Fellowship from the Japan Society for the Promotion of Science.
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Publication: "Measurement and Modeling of Polarized Atmosphere at the South Pole with SPT-3G," https://arxiv.org/abs/2407.20579
Presenters
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Anna Coerver
- University of California, Berkeley