Details on the event


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Astrophysics Talk

Constraints on cosmological parameters from tSZ galaxy clusters

Laura Salvati (Institut d’Astrophysique Spatiale, CNRS)

Tuesday 16/04/2019 @ 14:00, Sala IV piano Battiferro

The thermal Sunyaev-Zel’dovich (tSZ) effect is one of the recent probes of cosmology and large-scale structures. In this talk we will review how we can extract cosmological information from galaxy clusters measured through the tSZ effect. We will highlight the main ingredients needed in the analysis (namely the mass function and the scaling relations) and how they affect the final cosmological constraints. I will show results from the combination of tSZ cluster number counts and power spectrum of hot gas, using the latest results from the Planck collaboration. I will focus on how the addition of tSZ power spectrum helps in improving the cosmological constraints, in particular when considering extensions to the standard model of cosmology. I will discuss also the well-known discrepancy between CMB primary anisotropies and clusters constraints. Part of the talk will be devoted to describe the effects of the mass bias, which is one of the most important sources of systematic errors when using tSZ clusters as a cosmological probe. I will analyse the effect of a mass-redshift variation of this quantity, also on the remaining discrepancy between CMB and tSZ results. On the one hand, I will show that we find a mild evidence of redshift dependence for the mass bias. On the other hand, I will discuss how this result depends on the cluster sample that we are considering, in particular on the clusters mass and redshift range.