Orateur
Description
Electrons with certain optical depth within galaxy groups and clusters Thomson scatter CMB photons out of and into the line of sight, an effect known as patchy screening. In this talk, I will propose a new "temperature inversion" (TI) estimator to detect this screening effect of the electrons. Our estimator is analogous to the 'shear only' and 'gradient inversion' estimators of CMB lensing. I will show that the screening signal is correlated with the local un-screened primary CMB temperature, whose sign alternates and averages to zero. As a result, all other foregrounds (CIB, tSZ, kSZ) cancel and do not bias our screening estimator. This is a big advantage over the traditional quadratic estimator (QE) proposed for the patchy screening which is biased by foregrounds and CMB lensing. I will identify the regimes where TI estimator outperforms QE in terms of SNR. If possible, I will also show results after applying our method to the CMB and galaxy data.
