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Geometry versus growth. Internal consistency of the flat LambdaCDM model with KiDS-1000

Ruiz-Zapatero, J; Stölzner, B; Joachimi, B; Asgari, M; Bilicki, M; Dvornik, A; Giblin, B; ... al, E; + view all (2021) Geometry versus growth. Internal consistency of the flat LambdaCDM model with KiDS-1000. Astronomy & Astrophysics 10.1051/0004-6361/202141350. (In press). Green open access

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Abstract

We carry out a multi-probe self-consistency test of the flat 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 Lambda Cold Dark Matter (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 S 8 persists at around 3σ, with a 1.5 % constraint of S 8 = 0.776+0.016 for −0.008 the combined probes. We also observe a less significant preference (at least 2σ) for higher values of the Hubble constant, H0 = 70.5+0.7 km s−1 Mpc−1 , as well as for lower values of the total matter density parameter Ωm = 0.289+0.007 compared to the full Planck −1.5 −0.005 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.

Type: Article
Title: Geometry versus growth. Internal consistency of the flat LambdaCDM model with KiDS-1000
Open access status: An open access version is available from UCL Discovery
DOI: 10.1051/0004-6361/202141350
Publisher version: https://doi.org/10.1051/0004-6361/202141350
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions.
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10135169
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