Weak galaxy lensing surveys have consistently reported low values of the S8 parameter compared to the Planck lambda cold dark matter (ΛCDM) cosmology. Amon & Efstathiou used KiDS1000 cosmic shear measurements to propose that this tension can be reconciled if the matter fluctuation spectrum is suppressed more strongly on nonlinear scales than assumed in stateoftheart hydrodynamical simulations. In this paper, we investigate cosmic shear data from the Dark Energy Survey (DES) Year 3. The nonlinear suppression of the matter power spectrum required to resolve the S8 tension between DES and the Planck ΛCDM 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 nonstandard 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 S8 tension is correct, the required suppression must extend into the mildly nonlinear regime to wavenumbers $k\sim 0.2 \, h\, {\rm Mpc}^{1}$. In addition, all measures of S8 using linear scales should agree with the Planck ΛCDM cosmology, an expectation that will be testable to high precision in the near future.
 Award ID(s):
 2009210
 NSFPAR ID:
 10349848
 Author(s) / Creator(s):
 ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
 Date Published:
 Journal Name:
 Monthly Notices of the Royal Astronomical Society
 Volume:
 510
 Issue:
 1
 ISSN:
 00358711
 Page Range / eLocation ID:
 216 to 229
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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