Measurement and Modeling of Polarized Atmosphere at the South Pole with SPT-3G

Understand

We present the detection and characterization of fluctuations in linearly polarized emission from the atmosphere above the South Pole.

• These measurements make use of data from the SPT-3G receiver on the South Pole Telescope in three frequency bands centered at 95, 150, and 220 GHz.
• We use the cross-correlation between detectors to produce an unbiased estimate of the power in Stokes I, Q, and U parameters on large angular scales.
• Our results are consistent with the polarized signal being produced by the combination of Rayleigh scattering of thermal radiation from the ground and thermal emission from a population of horizontally aligned ice crystals with an anisotropic distribution described by Kolmogorov turbulence.