CMB B-mode studies are amongst the most exciting, contemporary endeavors in the field of cosmology. They are broadly expected to provide a new, unique window on the physics of the very early Universe, giving a very strong evidence in favor of inflation as a correct paradigm, within which to model this phase of the Universe's evolution, but also potentially constraining some of the fundamental energy scales of physics. These are hoped to provide some essential clues for high energy physics models.

In addition, thanks to the fact that some of the observed B-mode is converted from the E-mode signal due to the gravitational lensing of the CMB photons by the growing large scale structures, it could set unique complementary constraints on dark energy properties at the redshift z around 1-2 and on the masses of the neutrinos, with a precision surpassing the one expected of future laboratory experiments by a factor of at least 10 and sufficient to resolve the neutrino mass hierarchy problem.

These exciting goals can be only reached if the other emissions present in the microwave band, either due to Galactic or extra-galactic sources and commonly referred to as foregrounds, are properly modelled and removed from the observed data.

The objective of the internship will be to explore the precision limits to which this can be achieved within the framework of the maximum likelihood component separation techniques. The envisaged work will involve using the suite of numerical codes and foreground models developed by our group at APC and our collaborators and investigating the observational and data analysis set-ups ensuring the best results. The internship is expected to contribute to our understanding of what properties of the foregrounds play key roles in limiting our ability to remove them from the measured data and to what levels of precision one can realistically expect them to be removed. The work will also aim at providing prescriptions for the most effective observational set-ups and potentially set a ground for the novel, more efficient foreground separation approaches. All these issues constitute some of the most actively researched current topics in the field and the proposed project will allow the intern to get involved in, and contribute to, some of the most exciting research areas of present-day cosmology.

This internship could continue as a PhD project (see project “Search for primordial gravitational waves with the next generation of the CMB observatories” proposed by R. Stompor and J. Errard (see the APC website)) pending funds availability.