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KiDS-450: Testing extensions to the standard cosmological model

Joudaki, S; Mead, A; Blake, C; Choi, A; de Jong, J; Erben, T; Conti, IF; ... Viola, M; + view all (2017) KiDS-450: Testing extensions to the standard cosmological model. Monthly Notices of the Royal Astronomical Society , 471 (2) pp. 1259-1279. 10.1093/mnras/stx998. Green open access

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Abstract

We test extensions to the standard cosmological model with weak gravitational lensing tomography using 450 deg2 of imaging data from the Kilo Degree Survey (KiDS). In these extended cosmologies, which include massive neutrinos, nonzero curvature, evolving dark energy, modified gravity, and running of the scalar spectral index, we also examine the discordance between KiDS and cosmic microwave background measurements from Planck. The discordance between the two datasets is largely unaffected by a more conservative treatment of the lensing systematics and the removal of angular scales most sensitive to nonlinear physics. The only extended cosmology that simultaneously alleviates the discordance with Planck and is at least moderately favoured by the data includes evolving dark energy with a time-dependent equation of state (in the form of the w w 0 − w w a parameterization). In this model, the respective S 8 =σ 8 Ω m /0.3 − − − − − − √ S8=σ8Ωm/0.3 constraints agree at the 1σ level, and there is ‘substantial concordance’ between the KiDS and Planck datasets when accounting for the full parameter space. Moreover, the Planck constraint on the Hubble constant is wider than in ΛCDM and in agreement with the Riess et al. (2016) direct measurement of H0. The dark energy model is moderately favoured as compared to ΛCDM when combining the KiDS and Planck measurements, and marginalized constraints in the w w 0 − w w a plane are discrepant with a cosmological constant at the 3σ level. KiDS further constrains the sum of neutrino masses to 4.0 eV (95% CL), finds no preference for time or scale dependent modifications to the metric potentials, and is consistent with flatness and no running of the spectral index.

Type: Article
Title: KiDS-450: Testing extensions to the standard cosmological model
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/stx998
Publisher version: https://doi.org/10.1093/mnras/stx998
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Keywords: surveys, cosmology: theory, gravitational lensing: weak
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.ucl.ac.uk/id/eprint/1561245
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