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KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear

Joudaki, S; Hildebrandt, H; Traykova, D; Chisari, NE; Heymans, C; Kannawadi, A; Kuijken, K; ... van den Busch, JL; + view all (2020) KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear. Astronomy & Astrophysics , 638 , Article L1. 10.1051/0004-6361/201936154. Green open access

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Abstract

We present a combined tomographic weak gravitational lensing analysis of the Kilo Degree Survey (KV450) and the Dark Energy Survey (DES-Y1). We homogenize the analysis of these two public cosmic shear datasets by adopting consistent priors and modeling of nonlinear scales, and determine new redshift distributions for DES-Y1 based on deep public spectroscopic surveys. Adopting these revised redshifts results in a 0.8σ reduction in the DES-inferred value for S​8, which decreases to a 0.5σ reduction when including a systematic redshift calibration error model from mock DES data based on the MICE2 simulation. The combined KV450+DES-Y1 constraint on S8 = 0.762−0.024+0.025 is in tension with the Planck 2018 constraint from the cosmic microwave background at the level of 2.5σ. This result highlights the importance of developing methods to provide accurate redshift calibration for current and future weak-lensing surveys.

Type: Article
Title: KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear
Open access status: An open access version is available from UCL Discovery
DOI: 10.1051/0004-6361/201936154
Publisher version: https://doi.org/10.1051/0004-6361/201936154
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: cosmology: observations / galaxies: photometry / gravitational lensing: weak / surveys
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/10100944
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