Dark Energy Survey Year 1 results: cosmological constraints from cosmic shear

Troxel, M A, MacCrann, N, Zuntz, J, Krause, E, Dodelson, S, Gruen, D, Blazek, J, Friedrich, O, Samuroff, S, Prat, J, Romer, A K, The DES Collobration, and others, (2018) Dark Energy Survey Year 1 results: cosmological constraints from cosmic shear. Physical Review D, 98 (4). 043528 1-33. ISSN 2470-0010

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Abstract

We use 26 million galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg 2 of the sky to produce the most significant measurement of cosmic shear in a galaxy survey to date. We constrain cosmological parameters in both the flat Λ CDM and w CDM models, while also varying the neutrino mass density. These results are shown to be robust using two independent shape catalogs, two independent \photoz\ calibration methods, and two independent analysis pipelines in a blind analysis. We find a 3.5\% fractional uncertainty on σ 8 (Ω m /0.3) 0.5 =0.782 +0.027 −0.027 at 68\% CL, which is a factor of 2.5 improvement over the fractional constraining power of our DES Science Verification results. In w CDM, we find a 4.8\% fractional uncertainty on σ 8 (Ω m /0.3) 0.5 =0.777 +0.036 −0.038 and a dark energy equation-of-state w=−0.95 +0.33 −0.39. We find results that are consistent with previous cosmic shear constraints in σ 8 -- Ω m, and see no evidence for disagreement of our weak lensing data with data from the CMB. Finally, we find no evidence preferring a w CDM model allowing w≠−1 . We expect further significant improvements with subsequent years of DES data, which will more than triple the sky coverage of our shape catalogs and double the effective integrated exposure time per galaxy.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QC Physics
Depositing User: Alice Jackson
Date Deposited: 14 Dec 2018 14:46
Last Modified: 02 Jul 2019 13:34
URI: http://sro.sussex.ac.uk/id/eprint/80475

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