11:00 am–12:00 pm ERC 401
Abhishek Maniyar (Stanford University) "First detection of the patchy screening of the CMB photons"
Electrons 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 effect. I will show that the estimator is unbiased to foregrounds (CIB, tSZ, kSZ). This is a big advantage over the traditional “quadratic estimator” for the patchy screening which is biased by foregrounds and CMB lensing. I will then present the first detection of the patchy screening effect through cross-correlation of the Atacama Cosmology Telescope and Planck satellite CMB data, and unWISE galaxies. This measurement, exceeding 7-sigma in significance, directly probes the distribution of electrons around these galaxies. Finally, I will discuss the prospects of this technique to constrain galaxy evolution models.