Cosmological constraints from the 100-deg2 weak-lensing survey

Authors

  • Jonathan Benjamin,

    Corresponding author
    1. University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1
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  • Catherine Heymans,

    1. University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1
    2. Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie – Paris, 98 bis bd Arago, 75014 Paris, France
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  • Elisabetta Semboloni,

    1. Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie – Paris, 98 bis bd Arago, 75014 Paris, France
    2. Argelander-Institut für Astronomie (AIfA), Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
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  • Ludovic Van Waerbeke,

    1. University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1
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  • Henk Hoekstra,

    1. Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada V8P 5C2
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  • Thomas Erben,

    1. Argelander-Institut für Astronomie (AIfA), Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
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  • Michael D. Gladders,

    1. Department of Astronomy & Astrophysics, University of Chicago, Chicago, IL 60637, USA
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  • Marco Hetterscheidt,

    1. Argelander-Institut für Astronomie (AIfA), Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
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  • Yannick Mellier,

    1. Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie – Paris, 98 bis bd Arago, 75014 Paris, France
    2. Argelander-Institut für Astronomie (AIfA), Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
    3. Observatoire de Paris, LERMA, 61, avenue de l'Observatoire, 75014 Paris, France
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  • H. K. C. Yee

    1. Department of Astronomy & Astrophysics, University of Toronto, Toronto, ON, Canada M5S 3H4
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Based on observations obtained at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada (NRCC), the Institut des Sciences de l'Univers (INSU) of the Centre National de la Recherche Scientifique (CNRS) and the University of Hawaii (UH).

E-mail: jonben@phas.ubc.ca

ABSTRACT

We present a cosmic shear analysis of the 100-deg2 weak-lensing survey, combining data from the CFHTLS-Wide, RCS, VIRMOS-DESCART and GaBoDS surveys. Spanning ∼100 deg2, with a median source redshift z∼ 0.78, this combined survey allows us to place tight joint constraints on the matter density parameter Ωm, and the amplitude of the matter power spectrum σ8, finding σ8m/0.24)0.59= 0.84 ± 0.05. Tables of the measured shear correlation function and the calculated covariance matrix for each survey are included as supplementary material to the online version of this article.

The accuracy of our results is a marked improvement on previous work owing to three important differences in our analysis; we correctly account for sample variance errors by including a non-Gaussian contribution estimated from numerical simulations; we correct the measured shear for a calibration bias as estimated from simulated data; we model the redshift distribution, n(z), of each survey from the largest deep photometric redshift catalogue currently available from the CFHTLS-Deep. This catalogue is randomly sampled to reproduce the magnitude distribution of each survey with the resulting survey-dependent n(z) parametrized using two different models. While our results are consistent for the n(z) models tested, we find that our cosmological parameter constraints depend weakly (at the 5 per cent level) on the inclusion or exclusion of galaxies with low-confidence photometric redshift estimates (z > 1.5). These high-redshift galaxies are relatively few in number but contribute a significant weak-lensing signal. It will therefore be important for future weak-lensing surveys to obtain near-infrared data to reliably determine the number of high-redshift galaxies in cosmic shear analyses.

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