Kavli Affiliate: George Efstathiou
| Summary:
Weak galaxy lensing surveys have consistently reported low values of the $S_8$ parameter compared to the $textitPlanck ΛrmCDM$ cosmology. Amon & Efstathiou (2022) used KiDS-1000 cosmic shear measurements to propose that this tension can be reconciled if the matter fluctuation spectrum is suppressed more strongly on non-linear scales than assumed in state-of-the-art hydrodynamical simulations. In this paper, we investigate cosmic shear data from the Dark Energy Survey (DES) Year 3. The non-linear suppression of the matter power spectrum required to resolve the $S_8$ tension between DES and the $textitPlanck ΛrmCDM$ model is not as strong as inferred using KiDS data, but is still more extreme than predictions from recent numerical simulations. An alternative possibility is that non-standard dark matter contributes to the required suppression. We investigate the redshift and scale dependence of the suppression of the matter power spectrum. If our proposed explanation of the $S_8$ tension is correct, the required suppression must extend into the mildly non-linear regime to wavenumbers $ksim 0.2 h rm Mpc^-1$. In addition, all measures of $S_8$ using linear scales should agree with the $textitPlanck ΛrmCDM$ cosmology, an expectation that will be testable to high precision in the near future.
| Search Query: arXiv Query: search_query=au:”Efstathiou George”&id_list=&start=0&max_results=10
Read More