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

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 compare cosmological constraints between subsets of the KiDS-Legacy dataset split by redshift, angular scale, galaxy colour and spatial region. We also review a range of two-point cosmic shear statistics. With the data passing all our 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 find constraints consistent with Planck measurements of the cosmic microwave background with $S_8\equiv \ddot{I}{ƒ}_8\sqrt{\hat{I}{\text{c◯}}_{\mathrm{m}}/0.3}=0.814_{-0.012}^{+0.011}$ and $\ddot{I}{ƒ}_8=0.802_{-0.018}^{+0.022}$.

25 pages, 16 figures, 7 tables, published in A&A