Unveiling the complexity of radio foregrounds for the detectability of the CMB polarization B-mode

One of the main challenges in Cosmology is the detection of the primordial B-mode of CMB polarization, which would constitute a confirmation of the inflationary period of the Universe. However, the presence of different contaminants, mainly coming from the emissions of our own Galaxy, constitutes one of the major limiting factors to constrain reliably the existence of the B-modes. Indeed, the success of future CMB polarization experiments lies in the improved understanding and removal capability of foreground emissions.RadioForegrounds+ will provide a state-of-the art description of the highly complex properties of the polarised radio emission from our Galaxy, in particular the synchrotron and the anomalous microwave emissions, as well as of the population of radio sources. It will also provide an unprecedentedly thorough description of the intensity signal. This goal can only be achieved by combining the ESA’s Planck satellite maps (30-857GHz) with the unique low frequency experiments considered in this proposal: QUIJOTE (10-40 GHz), C-BASS (5 GHz) and S-PASS (2.3 GHz), by counting within the consortium with experts on the previous data sets (including the teams responsible for QUIJOTE and C-BASS) and by using the most advanced analysis techniques.The combination of these datasets will provide high-level data products, that will range from more complete radio catalogues, including fainter sources and additional frequency coverage, to new component separated maps in wider regions of the sky. These new data products and models will be made available to the scientific community through widely-used platforms, increasing the scientific return and the impact of the project. We will also provide forecasts of the impact of radio foregrounds on the detectability of the B-mode of polarization for future CMB experiments. The resulting analyses will play a key role in preparing and supporting future international CMB missions as LiteBIRD or ground-based efforts as CMB-S4.