KiDS+VIKING-450 and DES-Y1 combined: mitigating baryon feedback uncertainty with COSEBIs

Journal article

We present cosmological constraints from a joint cosmic shear analysis of the Kilo-Degree Survey (KV450) and the Dark Energy Survey (DES-Y1), which were conducted using Complete Orthogonal Sets of E/B-Integrals (COSEBIs). With COSEBIs, we isolated any B-modes that have a non-cosmic shear origin and demonstrate the robustness of our cosmological E-mode analysis as no significant B-modes were detected. We highlight how COSEBIs are fairly insensitive to the amplitude of the non-linear matter power spectrum at high k-scales, mitigating the uncertain impact of baryon feedback in our analysis. COSEBIs, therefore, allowed us to utilise additional small-scale information, improving the DES-Y1 joint constraints on S8 = σ8(Ωm/0.3)0.5 and Ωm by 20%. By adopting a flat ΛCDM model we find S8 = 0.755−0.021+0.019, which is in 3.2σ tension with the Planck Legacy analysis of the cosmic microwave background.

Authors: Asgari, M; Troster, T; Heymans, C; Hildebrandt, H; van den Busch, JL

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: EDP Sciences
• Journal: Astronomy and Astrophysics
• Volume: 634
• Article number: A127
• Publication date: 2020-02-24
• Acceptance date: 2020-01-21
• DOI: 10.1051/0004-6361/201936512
• EISSN: 1432-0746
• ISSN: 0004-6361
• Language: English
• Keywords: surveys; cosmological parameters; FFR; methods: data analysis; large-scale structure of universe; gravitational lensing: weak; methods: statistical