Orateur
Description
Because they probe two different, complementary aspects of the same question of cosmic reionisation (where is the neutral gas for one, and where are the free electrons for the other), the high-redshift 21cm signal and CMB secondary anisotropies such as the kSZ and Thomson screening are highly complementary. Their cross-correlation has been shown in many works to be a promising observable for cosmology, with sufficient signal-to-noise ratio (SNR) to be observable either today or with upcoming telescopes. However, none of these forecasts took the reality of observations into account. In this talk, I will show how the predicted SNR evolve when considering the specificities of each telescope used for the cross-correlation, such as precise uv/sky coverage, as well as the impact of foregrounds. Naturally, the SNR take a big hit, so I will present various observing and analysis strategies to gain back the lost SNR and reach a detection of the cross-correlation of the 21cm signal with CMB optical depth fluctuations (also called "patchy tau").