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Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Modeling Uncertainty

Secco, LF; Samuroff, S; Krause, E; Jain, B; Blazek, J; Raveri, M; Campos, A; ... To, C; + view all (2022) Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Modeling Uncertainty. Physical Review D , 105 , Article 023515. 10.1103/PhysRevD.105.023515. Green open access

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Abstract

This work and its companion paper, Amon et al. [Phys. Rev. D 105, 023514 (2022)], present cosmic shear measurements and cosmological constraints from over 100 million source galaxies in the Dark Energy Survey (DES) Year 3 data. We constrain the lensing amplitude parameter S 8 ≡ σ 8 √ Ω m / 0.3 at the 3% level in Λ CDM : S 8 = 0.75 9 + 0.025 − 0.023 (68% CL). Our constraint is at the 2% level when using angular scale cuts that are optimized for the Λ CDM analysis: S 8 = 0.77 2 + 0.018 − 0.017 (68% CL). With cosmic shear alone, we find no statistically significant constraint on the dark energy equation-of-state parameter at our present statistical power. We carry out our analysis blind, and compare our measurement with constraints from two other contemporary weak lensing experiments: the Kilo-Degree Survey (KiDS) and Hyper-Suprime Camera Subaru Strategic Program (HSC). We additionally quantify the agreement between our data and external constraints from the Cosmic Microwave Background (CMB). Our DES Y3 result under the assumption of Λ CDM is found to be in statistical agreement with Planck 2018, although favors a lower S 8 than the CMB-inferred value by 2.3 σ (a p -value of 0.02). This paper explores the robustness of these cosmic shear results to modeling of intrinsic alignments, the matter power spectrum and baryonic physics. We additionally explore the statistical preference of our data for intrinsic alignment models of different complexity. The fiducial cosmic shear model is tested using synthetic data, and we report no biases greater than 0.3 σ in the plane of S 8 × Ω m caused by uncertainties in the theoretical models.

Type: Article
Title: Dark Energy Survey Year 3 Results: Cosmology from Cosmic Shear and Robustness to Modeling Uncertainty
Open access status: An open access version is available from UCL Discovery
DOI: 10.1103/PhysRevD.105.023515
Publisher version: http://dx.doi.org/10.1103/PhysRevD.105.023515
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Astro-ph.CO, astro-ph.CO
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10142236
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