Retrieving cosmological information from small-scale CMB foregrounds I. The thermal Sunyaev Zel'dovich effect

Understand

We propose a new analysis of small scale CMB data by introducing the cosmological dependency of the foreground signals, focusing first on the thermal Sunyaev-Zel'dovich (tSZ) power spectrum, derived from the halo model.

• We analyse the latest observations by the South Pole Telescope (SPT) of the high-$\ell$ power (cross) spectra at 90, 150 and 220 GHz, as the sum of CMB and tSZ signals, both depending on cosmological parameters, and remaining contaminants.
• In order to perform faster analyses, we propose a new tSZ modelling based on machine learning algorithms (namely Random Forest).
• We show that the additional information contained in the tSZ power spectrum tightens constraints on cosmological and tSZ scaling relation parameters.