A non-linear solution to the S8 tension?
A non-linear solution to the S8 tension?
复制标题
S8 张力的非线性解决方案？
DOI：
10.1093/mnras/stac2429
复制
发表时间：
2022
影响因子：
4.8
通讯作者：
G. Efstathiou
中科院分区：
文献类型：
--
作者：
A. Amon;G. Efstathiou
弱星系透镜观测一直报告物质起伏光谱的振幅低于普朗克青睐的Λcdm宇宙学中预期的S8参数。然而，膨胀历史遵循了普朗克Λcdm宇宙学的高精度预测，宇宙微波背景各向异性的透镜测量也是如此。红移空间扭曲的测量似乎也与普朗克Λcdm一致。在这篇文章中，我们认为，如果物质功率谱在非线性尺度上受到比在弱星系透镜分析中假设的更强的抑制，这些观测结果可以与普朗克Λ清洁发展机制宇宙学相一致。我们通过拟合一个单参数模型来证明这一点，该模型表征了对非线性功率谱的抑制，与KILDS-1000弱透镜测量结果相吻合。这种抑制可能是由于暗物质的新性质影响了非线性尺度，或者是因为物质涨落对重子反馈过程的反应比最近的宇宙学模拟所预期的更强。我们提出的解释可以通过在线性尺度上测量物质涨落谱的幅度来检验，特别是通过即将到来的星系和类星体红移测量的高精度红移空间扭曲测量。
Weak galaxy lensing surveys have consistently reported a lower amplitude for the matter fluctuation spectrum, as measured by the S8 parameter, than expected in the ΛCDM cosmology favoured by Planck. However, the expansion history follows the predictions of the Planck ΛCDM cosmology to high accuracy, as do measurements of lensing of the cosmic microwave background anisotropies. Redshift space distortion measurements also appear to be consistent with Planck ΛCDM. In this paper, we argue that these observations can be reconciled with the Planck ΛCDM cosmology if the matter power spectrum is suppressed more strongly on non-linear scales than assumed in analyses of weak galaxy lensing. We demonstrate this point by fitting a one-parameter model, characterizing a suppression of the non-linear power spectrum, to the KiDS-1000 weak lensing measurements. Such a suppression could be attributed to new properties of the dark matter that affect non-linear scales, or to a response of the matter fluctuations to baryonic feedback processes that are stronger than expected from recent cosmological simulations. Our proposed explanation can be tested using measurements of the amplitude of the matter fluctuation spectrum on linear scales, in particular via high precision redshift space distortion measurements from forthcoming galaxy and quasar redshift surveys.