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

¹ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
e-mail: ma@roe.ac.uk
² Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
³ Ruhr-University Bochum, Astronomical Institute, German Centre for Cosmological Lensing, Universitätsstr. 150, 44801 Bochum, Germany
⁴ Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA
⁵ Center for Theoretical Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
⁶ Centre for Astrophysics & Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia
⁷ Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
⁸ Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
⁹ INAF – Astronomical Observatory of Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
¹⁰ Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
¹¹ Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
¹² INAF – Osservatorio Astronomico di Padova, via dell’Osservatorio 5, 35122 Padova, Italy
¹³ Shanghai Astronomical Observatory (SHAO), Nandan Road 80, Shanghai 200030, PR China
¹⁴ University of Chinese Academy of Sciences, Beijing 100049, PR China
¹⁵ Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands

Received: 30 July 2020
Accepted: 12 October 2020

Abstract

We present cosmological constraints from a cosmic shear analysis of the fourth data release of the Kilo-Degree Survey (KiDS-1000), which doubles the survey area with nine-band optical and near-infrared photometry with respect to previous KiDS analyses. Adopting a spatially flat standard cosmological model, we find S₈ = σ₈(Ω_m/0.3)^0.5 = 0.759_−0.021^+0.024 for our fiducial analysis, which is in 3σ 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 the 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 S₈ constraints to be robust and dominated by statistical errors. Our cosmological analysis of different divisions of the data passes 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.