Sixteenth Marcel Grossmann Meeting

Quantifying the S8 tension with the Redshift Space Distortion data set

5 Jul 2021, 18:20

22m

Invited talk in the parallel session Status of the H_0 and sigma_8 tensions: theoretical models and model-independent constraints Status of the H_0 and Sigma_8 Tensions: Theoretical Models and Model-Independent Constraints

Speaker

David Benisty (University of Cambridge)

Description

One problem of the ΛCDM model is the tension between the S8 found in Cosmic Microwave Background (CMB) experiments and the smaller one obtained from large-scale observations in the late
Universe. The σ8 quantifies the relatively high level of clustering. Bayesian Analysis of the Redshift
Space Distortion (RSD) selected data set yields: S8 = 0.700+0.038
−0.037. The fit has 3σ tension with the
Planck 2018 results. With Gaussian processes method a model-independent reconstructions of the
growth history of matter in-homogeneity is studied. The fit yields S8 = 0.707+0.085
−0.085, 0.701+0.089
−0.089,
and 0.731+0.063
−0.062 for different kernels. The tension reduces and being smaller then 1.5 σ. With future measurements the tension may be reduced, but the possibility the tension is real is a plausible
situation.

Presentation materials

Quantifying the S_8 tension with the.pdf