KiDS-1000 Cosmology: Cosmic shear constraints and comparison between two point statistics

TL;DR

This paper presents cosmological constraints from KiDS-1000 cosmic shear data, compares different statistical methods, and finds results consistent across methods but in tension with Planck CMB predictions, highlighting robustness and systematic considerations.

Contribution

First comprehensive KiDS-1000 cosmic shear analysis comparing multiple point statistics and assessing their systematic sensitivities.

Findings

$S_8$ measured at 0.759 with ~3% statistical uncertainty.

Fiducial analysis results are consistent across different shear statistics.

Results are robust to systematic variations and data divisions.

Abstract

We present cosmological constraints from a cosmic shear analysis of the fourth data release of the Kilo-Degree Survey (KiDS-1000), doubling the survey area with nine-band optical and near-infrared photometry with respect to previous KiDS analyses. Adopting a spatially flat $\Lambda$CDM model, we find $S_8 = \sigma_8 (\Omega_{\rm m}/0.3)^{0.5} = 0.759^{+0.024}_{-0.021}$ for our fiducial analysis, which is in $3\sigma$ tension with the prediction of the Planck Legacy analysis of the cosmic microwave background. We compare our fiducial COSEBIs (Complete Orthogonal Sets of E/B-Integrals) analysis with complementary analyses of the two-point shear correlation function and band power spectra, finding results to be in excellent agreement. We investigate the sensitivity of all three statistics to a number of measurement, astrophysical, and modelling systematics, finding our $S_8$ constraints to be robust and dominated by statistical errors. Our cosmological analysis of different divisions of the data pass the Bayesian internal consistency tests, with the exception of the second tomographic bin. As this bin encompasses low redshift galaxies, carrying insignificant levels of cosmological information, we find that our results are unchanged by the inclusion or exclusion of this sample.