Atmospheric fluctuation is one of the sources of low-frequency
noise in ground-based CMB experiments. Since atmospheric emissions are
almost unpolarized, they do not directly increase the noise of
polarization measurements as far as instruments are well-calibrated.
Tropospheric ice clouds, however, scatter upwelling thermal radiations
and produce polarized signals. In practice, most of the...
Distortions in the primordial cosmic microwave background polarization can correspond to real or conjectured cosmological signals such as gravitational lensing, patchy reionization, and cosmic birefringence, but they can also arise from instrumental systematics such as detector gain fluctuation, differential gain, differential pointing, polarization angle rotation. The distortion fields...
In a ground-based CMB experiment, the detection is contaminated by the atmosphere and ground emissions, and there are also temperature-to-polarization leakages. Thus, the time-ordered data (TOD) need to be filtered to reduce those contaminations. However, the filtering will inevitably remove some CMB signals and distort the rest. Especially, it causes additional E-to-B leakage and B-mode...
A crucial problem for part-sky analysis of CMB polarization is the E-B leakage problem. Such leakage arises from the presence of `ambiguous' modes that satisfy properties of both E and B modes. Solving this problem is critical for primordial polarization B mode detection in part-sky CMB polarization experiments. In this work we introduce a new method for reducing the leakage. We demonstrate...
