04 January 2022Séminaire – Alain Blanchard (IRAP)

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Is there a tension on the amplitude of matter fluctuations in the LCDM model?

Abstract

The results of the eBOSS survey provide the best current measurements of the properties of the distribution of galaxies, constituting the summary of a long-term SDSS effort. Among those, the amplitude of the matter fluctuations, expressed in terms of the S8 parameter, is measured at several redshifts thanks to the “RSD” (redshift space distortion). These data by themselves do not provide strong constraints but are powerful when used in combination. In this talk, I will discuss the impact of the eBOSS measurements, when combined with the Planck data, for the standard model and discuss the consequences for the S8 tension question.