Orateur
Description
CMB observations from ground-based observatories are limited in sensitivity by the fluctuating emission from the Earth's atmosphere, mostly due to water vapor inhomogeneities. Standard mitigation techniques either remove a significant fraction of the cosmological signal (low-frequency filtering) or leave residuals from instrumental imperfections and polarized atmospheric emission (pair-differencing, half-wave plate modulation). We present a new data analysis framework in which a multi-frequency focal plane includes detectors dedicated to atmosphere monitoring. Time-domain component separation applied to these monitors yields atmospheric templates, which are then used to subtract the atmosphere from the science detectors. We introduce an atmospheric decontamination factor, $A^\mathrm{atm}_\ell$, to quantify the reduction of atmospheric power in the maps. In simulations, this pipeline leaves ~4000 times less atmospheric power than a standard filtering and binning pipeline over $30 \leq \ell \leq 300$.