KiDS-Legacy: Consistency of cosmic shear measurements and joint cosmological constraints with external probes

¹ Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB), German Centre for Cosmological Lensing, 44780 Bochum, Germany
² School of Mathematics, Statistics and Physics, Newcastle University, Herschel Building, NE1 7RU Newcastle-upon-Tyne, United Kingdom
³ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, United Kingdom
⁴ Leiden Observatory, Leiden University, PO Box 9513 2300RA Leiden, The Netherlands
⁵ Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
⁶ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
⁷ Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, ON N2L 3G1, Canada
⁸ Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada
⁹ Institute for Theoretical Physics, Utrecht University, Princetonplein 5, 3584CC Utrecht, The Netherlands
¹⁰ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Av. Complutense 40, E-28040 Madrid, Spain
¹¹ Institute of Cosmology & Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX, United Kingdom
¹² Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria
¹³ Dipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Via Piero Gobetti 93/2, I-40129 Bologna, Italy
¹⁴ Istituto Nazionale di Astrofisica (INAF) – Osservatorio di Astrofisica e Scienza dello Spazio (OAS), Via Piero Gobetti 93/3, I-40129 Bologna, Italy
¹⁵ Istituto Nazionale di Fisica Nucleare (INFN) – Sezione di Bologna, viale Berti Pichat 6/2, I-40127 Bologna, Italy
¹⁶ INAF – Osservatorio Astronomico di Padova, Via dell’Osservatorio 5, 35122 Padova, Italy
¹⁷ Institute for Computational Cosmology, Ogden Centre for Fundament Physics – West, Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
¹⁸ Centre for Extragalactic Astronomy, Ogden Centre for Fundament Physics – West, Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
¹⁹ Center for Theoretical Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
²⁰ Institute for Particle Physics and Astrophysics, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
²¹ Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain
²² Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
²³ Donostia International Physics Center, Manuel Lardizabal Ibilbidea, 4, 20018 Donostia, Gipuzkoa, Spain
²⁴ The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm, Sweden
²⁵ Imperial Centre for Inference and Cosmology (ICIC), Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
²⁶ Zentrum für Astronomie, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany
²⁷ Institute for Theoretical Physics, Philosophenweg 16, D-69120 Heidelberg, Germany
²⁸ Department of Physics “E. Pancini” University of Naples Federico II C.U. di Monte Sant’Angelo Via Cintia, 21 ed. 6, 80126 Naples, Italy
²⁹ INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli, Italy
³⁰ INFN, Sez. di Napoli, via Cintia, 80126 Napoli, Italy
³¹ Kapteyn Institute, University of Groningen, PO Box 800 NL 9700 AV, Groningen

^⋆ Corresponding author: stoelzner@astro.rub.de

Received: 31 March 2025
Accepted: 31 July 2025

Abstract

We present a cosmic shear consistency analysis of the final data release from the Kilo-Degree Survey (KiDS-Legacy). By adopting three tiers of consistency metrics, we compared cosmological constraints between subsets of the KiDS-Legacy dataset split by redshift, angular scale, galaxy colour, and spatial region. We also reviewed a range of two-point cosmic shear statistics. As all the data passed our set of consistency metric tests, we demonstrate that KiDS-Legacy is the most internally consistent KiDS catalogue to date. In a joint cosmological analysis of KiDS-Legacy and DES Y3 cosmic shear, combined with data from the Pantheon+ Type Ia supernovae compilation and baryon acoustic oscillations from DESI Y1, we report constraints that are consistent with Planck measurements of the cosmic microwave background, with S₈ ≡ √σ₈Ω_m/0.3 = 0.814_−0.012^+0.011 and σ₈ = 0.802_−0.018^+0.022.