Final steps in stage-iii surveys: kilo-degree team gathers at OKC for 6x2pt legacy analysis workshop
Last week, a small team of cosmologists from Spain, Germany, the Netherlands, and Sweden gathered at the Oskar Klein Centre (OKC) in Stockholm for an intensive workshop focused on finalizing the Kilo-Degree Survey (KiDS) 6x2pt Legacy Analysis.
Image: The soft glow of the Milky Way pours down like a waterfall over the VLT Survey Telescope (VST) at ESO’s Paranal Observatory.
Earlier this year, the KiDS team released its Legacy Weak Lensing analysis, providing detailed insights into the long-standing cosmological puzzle known as the S₈ tension—an ongoing discrepancy between the observed growth of cosmic structures and predictions based on the early Universe. The recent 6x2pt analysis directly builds upon this work, integrating weak lensing measurements with galaxy clustering data from KiDS photometry and spectroscopic information from the BOSS survey.
The term “6x2pt” refers to six unique two-point correlation functions involving galaxy positions and shapes, widely recognized as the gold standard method for Stage-III cosmological surveys. These surveys have laid critical groundwork for upcoming Stage-IV missions, including Euclid, LSST, and DESI.
During the OKC workshop, participants actively refined data measurements, enhanced theoretical models, and addressed intricate but crucial details to ensure the completeness of this cosmological analysis. This collaborative effort will leave a lasting scientific legacy and will set important benchmarks for future precision cosmology.
Image: The group hard at work!
The workshop also emphasized growing collaborations between KiDS and OKC. Notably, master’s student Xander Nooderloos from Utrecht University is currently completing his Master's project at OKC, co-supervised by Prof. Elisa Chisari, a prominent figure in both KiDS and LSST. Nooderloos’ research aligns directly with the themes of the workshop.
Dr. Arthur Loureiro, researcher at OKC and workshop organizer, underscored the wider significance of the recent work: “The tools and methodologies we developed during this week are crucial for my project funded by the Swedish National Space Agency, which aims to measure the mass of the lightest neutrino. The 6x2pt analysis will act as a pathfinder for our future analysis using data from the Euclid mission.”
With next-generation cosmological surveys on the horizon, the KiDS 6x2pt analysis exemplifies how meticulous and collaborative science can significantly advance our understanding of the Universe—even when conducted by a relatively small team.
Last updated: 2026-01-28
Source: Oskar Klein Centre