Sommaire:

The ΛCDM concordance model is very successful at describing our Universe with high accuracy and only a few parameters. Despite its successes, a few persistent tensions remains to this day: most notably, the best-fit ΛCDM model, as derived from the Planck CMB data, largely overpredicts the abundance of Sunyaev–Zel’dovich clusters when using their standard mass calibration. Whether this is the sign of an incorrect calibration or the need for new physics remains a matter of debate. In this talk, I will present the results from our exploration of extensions of the standard model -- massive neutrinos and a simple modified gravity model -- and their ability to release the aforementioned tension, pitted against a potential bias in the mass calibration of clusters. Under certain assumptions, we find that our conclusions may call for new physics in the gravitational sector.

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