Orateur
Description
The thermal Sunyaev-Zel’dovich effect refers to a spectral distortion in the cosmic microwave background (CMB) due to the inverse-Compton scattering of CMB photons off free, energetic electrons present in the Universe. It is primarily sourced by the electrons in the intracluster medium with smaller contributions from the intergalactic medium and the epoch of reionization. The amplitude of its monopole signal is a unique probe of the total thermal energy contained in the electrons in the Universe and of the period of structure formation with an upper limit |< y >| < 15 x 10^-6 set by the measurements from COBE-FIRAS. I will present new constraints on the all-sky y-distortion from re-analyzing FIRAS CMB monopole data. Additionally, I will present the first calculation of a tSZ-like distortion in the cosmic infrared background (CIB). CIB photons originating from the thermal dust emission in star-forming galaxies are expected to similarly inverse-Compton scatter. Using a halo model approach, we find that the resulting distortion in the CIB monopole spectrum has a positive (negative) peak amplitude of 4 Jy/sr (-5 Jy/sr) at 2260 GHz (940 GHz) and two null frequencies, at approximately 196 GHz and 1490 GHz. In addition to being a similar probe of the intervening free electrons, this signal would provide new insight into the star formation history of the Universe.
