Testing small-scale modifications in the primordial power spectrum with Subaru HSC cosmic shear, primary CMB and CMB lensing

Fuente: arXiv
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Auteurs principaux: Terasawa, Ryo, Takada, Masahiro, Sugiyama, Sunao, Kurita, Toshiki
Format: Preprint
Publié: 2025
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author Terasawa, Ryo
Takada, Masahiro
Sugiyama, Sunao
Kurita, Toshiki
author_facet Terasawa, Ryo
Takada, Masahiro
Sugiyama, Sunao
Kurita, Toshiki
contents Different cosmological probes, such as primary cosmic microwave background (CMB) anisotropies, CMB lensing, and cosmic shear, are sensitive to the primordial power spectrum (PPS) over different ranges of wavenumbers. In this paper, we combine the cosmic shear two-point correlation functions measured from the Subaru Hyper Suprime-Cam (HSC) Year 3 data with the Planck CMB data, and the ACT DR6 CMB lensing data to test modified shapes of the PPS at small scales, while fixing the background cosmology to the flat $Λ$CDM model. We consider various types of modifications to the PPS shape: the model with a running spectral index, the tanh-shaped model, the Starobinsky-type modification due to a sharp change in the inflaton potential, the broken power-law model, and the multiple broken power-law model. Although the HSC cosmic shear data is sensitive to the PPS at small scales, we find that the combined data remains consistent with the standard power-law PPS, i.e., the single power-law model, for the flat $Λ$CDM background. In other words, we conclude that the $S_8$ tension cannot be easily resolved by modifying the PPS within the $Λ$CDM background.
format Preprint
id arxiv_https___arxiv_org_abs_2503_20396
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Testing small-scale modifications in the primordial power spectrum with Subaru HSC cosmic shear, primary CMB and CMB lensing
Terasawa, Ryo
Takada, Masahiro
Sugiyama, Sunao
Kurita, Toshiki
Cosmology and Nongalactic Astrophysics
Different cosmological probes, such as primary cosmic microwave background (CMB) anisotropies, CMB lensing, and cosmic shear, are sensitive to the primordial power spectrum (PPS) over different ranges of wavenumbers. In this paper, we combine the cosmic shear two-point correlation functions measured from the Subaru Hyper Suprime-Cam (HSC) Year 3 data with the Planck CMB data, and the ACT DR6 CMB lensing data to test modified shapes of the PPS at small scales, while fixing the background cosmology to the flat $Λ$CDM model. We consider various types of modifications to the PPS shape: the model with a running spectral index, the tanh-shaped model, the Starobinsky-type modification due to a sharp change in the inflaton potential, the broken power-law model, and the multiple broken power-law model. Although the HSC cosmic shear data is sensitive to the PPS at small scales, we find that the combined data remains consistent with the standard power-law PPS, i.e., the single power-law model, for the flat $Λ$CDM background. In other words, we conclude that the $S_8$ tension cannot be easily resolved by modifying the PPS within the $Λ$CDM background.
title Testing small-scale modifications in the primordial power spectrum with Subaru HSC cosmic shear, primary CMB and CMB lensing
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2503.20396