Geometry versus growth: Internal consistency of the flat ΛCDM model with KiDS-1000

Journal Article · Thu Oct 28 00:00:00 EDT 2021 · Astronomy and Astrophysics

DOI:https://doi.org/10.1051/0004-6361/202141350· OSTI ID:1982284

Ruiz-Zapatero, Jaime  ^[1]; Stölzner, Benjamin ^[2]; Joachimi, Benjamin ^[2]; Asgari, Marika ^[3]; Bilicki, Maciej ^[4]; Dvornik, Andrej ^[5]; Giblin, Benjamin ^[3]; Heymans, Catherine ^[6]; Hildebrandt, Hendrik ^[5]; Kannawadi, Arun ^[7]; Kuijken, Konrad ^[8]; Tröster, Tilman ^[3]; van den Busch, Jan Luca ^[5]; Wright, Angus H. ^[5]

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1. Univ. of Oxford (United Kingdom); Univ. College London (United Kingdom)
2. Univ. College London (United Kingdom)
3. Univ. of Edinburgh, Scotland (United Kingdom)
4. Polish Academy of Sciences (PAS), Warsaw (Poland)
5. Ruhr Univ., Bochum (Germany)
6. Univ. of Edinburgh, Scotland (United Kingdom); Ruhr Univ., Bochum (Germany)
7. Princeton Univ., NJ (United States)
8. Leiden Univ. (Netherlands)

Here, we carry out a multi-probe self-consistency test of the flat Lambda Cold Dark Matter (ΛCDM) model with the aim of exploring potential causes of the reported tensions between high- and low-redshift cosmological observations. We divide the model into two theory regimes determined by the smooth background (geometry) and the evolution of matter density fluctuations (growth), each governed by an independent set of ΛCDM cosmological parameters. This extended model is constrained by a combination of weak gravitational lensing measurements from the Kilo-Degree Survey, galaxy clustering signatures extracted from Sloan Digital Sky Survey campaigns and the Six-Degree Field Galaxy Survey, and the angular baryon acoustic scale and the primordial scalar fluctuation power spectrum measured in Planck cosmic microwave background (CMB) data. For both the weak lensing data set individually and the combined probes, we find strong consistency between the geometry and growth parameters, as well as with the posterior of standard ΛCDM analysis. In the non-split analysis, for which one single set of parameters was used, tension in the amplitude of matter density fluctuations as measured by the parameter S₈ persists at around 3σ, with a 1.5% constraint of S₈ = 0.776$$_{–0.008}^{+0.016}$$ for the combined probes. We also observe a less significant preference (at least 2σ) for higher values of the Hubble constant, H₀ = 70.5$$_{–1.5}^{+0.7}$$ km s^–1 Mpc^–1, as well as for lower values of the total matter density parameter Ω_m = 0.289$$_{–0.005}^{+0.007}$$ compared to the full Planck analysis. Including the subset of the CMB information in the probe combination enhances these differences rather than alleviate them, which we link to the discrepancy between low and high multipoles in Planck data. Our geometry versus growth analysis does not yet yield clear signs regarding whether the origin of the discrepancies lies in ΛCDM structure growth or expansion history but holds promise as an insightful test for forthcoming, more powerful data.

• Research Organization: US Department of Energy (USDOE), Washington, DC (United States). Office of Science, Sloan Digital Sky Survey (SDSS)
• Sponsoring Organization: USDOE Office of Science (SC); National Aeronautics and Space Administration (NASA); Alfred P. Sloan Foundation
• OSTI ID: 1982284
• Journal Information: Astronomy and Astrophysics, Vol. 655; ISSN 0004-6361
• Publisher: EDP Sciences
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
cosmological parameters
data analysis
theory of cosmology
large-scale structure of the universe
weak gravitational lensing