Late-time suppression of structure growth as a solution for the $S_8$ tension
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866916736931987456 |
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| author | Terasawa, Ryo Takada, Masahiro Kurita, Toshiki Sugiyama, Sunao |
| author_facet | Terasawa, Ryo Takada, Masahiro Kurita, Toshiki Sugiyama, Sunao |
| contents | The $S_8$ value inferred from the Subaru Hyper Suprime-Cam (HSC) Year 3 cosmic shear data, under the assumption of the flat $Λ$CDM model, is 2-3$σ$ lower than that inferred from observations of the early-time universe, such as cosmic microwave background (CMB) anisotropy data. Resolving the $S_8$ tension requires a scenario in which structure formation on small scales is suppressed in the late universe. As potential solutions, we consider extended models both within and beyond the $Λ$CDM model -- models that incorporate parameterized baryonic feedback effects, the effect of varying neutrino mass, and modified structure growth, each of which can lead to a suppression of structure growth at lower redshifts, with its own distinct scale- and redshift-dependencies. In particular, we consider phenomenological modified gravity models in which the suppression of structure growth is triggered at lower redshifts, as dark energy ($Λ$) begins to dominate the background expansion. We show that the modified growth factor models -- especially those featuring more rapid growth suppression at lower redshifts -- provide an improved fit to the combined datasets of the HSC-Y3 cosmic shear correlation functions, the Planck CMB, and the ACT DR6 CMB lensing, compared to the fiducial $Λ$CDM model and the models including the baryonic effects or the massive neutrino effect within the the $Λ$CDM framework. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_09176 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Late-time suppression of structure growth as a solution for the $S_8$ tension Terasawa, Ryo Takada, Masahiro Kurita, Toshiki Sugiyama, Sunao Cosmology and Nongalactic Astrophysics The $S_8$ value inferred from the Subaru Hyper Suprime-Cam (HSC) Year 3 cosmic shear data, under the assumption of the flat $Λ$CDM model, is 2-3$σ$ lower than that inferred from observations of the early-time universe, such as cosmic microwave background (CMB) anisotropy data. Resolving the $S_8$ tension requires a scenario in which structure formation on small scales is suppressed in the late universe. As potential solutions, we consider extended models both within and beyond the $Λ$CDM model -- models that incorporate parameterized baryonic feedback effects, the effect of varying neutrino mass, and modified structure growth, each of which can lead to a suppression of structure growth at lower redshifts, with its own distinct scale- and redshift-dependencies. In particular, we consider phenomenological modified gravity models in which the suppression of structure growth is triggered at lower redshifts, as dark energy ($Λ$) begins to dominate the background expansion. We show that the modified growth factor models -- especially those featuring more rapid growth suppression at lower redshifts -- provide an improved fit to the combined datasets of the HSC-Y3 cosmic shear correlation functions, the Planck CMB, and the ACT DR6 CMB lensing, compared to the fiducial $Λ$CDM model and the models including the baryonic effects or the massive neutrino effect within the the $Λ$CDM framework. |
| title | Late-time suppression of structure growth as a solution for the $S_8$ tension |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2505.09176 |