KiDS + VIKING-450 cosmology with Bayesian hierarchical model redshift distributions

Journal article

Tomographic redshift distributions from photometric data are crucial ingredients in cosmic shear analysis, since they are required for the theoretical calculation of the signal based on the redshift distribution of the galaxies where the shear field is sampled. In this paper, we develop as a proof of concept Leistedt et al.’s template-based Bayesian Hierarchical Model framework into an application to weak lensing data by sampling the redshift distributions of the galaxies in the KiDS + VIKING-450 survey. We also use a principal component analysis to provide a set of representative templates drawn from a large superset. For computational tractability, subsets of galaxies are chosen to determine the redshift distributions, and we test the sensitivity of the cosmological inference to the subset chosen, finding it to be subdominant compared to the statistical error. We marginalize over the inferred redshift distributions and find that the Bayesian method increases the clustering parameter compared with previous studies, alleviating the tension with Planck, where , assuming flat lambda cold dark matter. The tension with Planck for this survey is reduced from to . We also infer a value for the matter density, .

Authors: Kyriacou, GT; Mootoovaloo, A; Heavens, AF; Jaffe, AH; Leclercq, F

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 549
• Issue: 2
• Article number: stag934
• Publication date: 2026-05-18
• Acceptance date: 2026-05-13
• DOI: 10.1093/mnras/stag934
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: gravitational lensing: weak; methods: statistical; methods: data analysis; techniques: photometric; cosmological parameters