Weak lensing from space: first cosmological constraints from three-point shear statistics

Authors

  • Elisabetta Semboloni,

    Corresponding author
    1. Leiden Observatory, Leiden University, NL-2333 CA Leiden, the Netherlands
    2. Argelander Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn, Germany
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  • Tim Schrabback,

    1. Leiden Observatory, Leiden University, NL-2333 CA Leiden, the Netherlands
    2. Argelander Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn, Germany
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  • Ludovic van Waerbeke,

    1. Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
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  • Sanaz Vafaei,

    1. Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
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  • Jan Hartlap,

    1. Argelander Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn, Germany
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  • Stefan Hilbert

    1. Argelander Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn, Germany
    2. Max Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
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  • Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archives at the Space Telescope European Coordinating Facility and the Space Telescope Science Institute, which is operated by the Association of the Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

E-mail: sembolon@strw.leidenuniv.nl

ABSTRACT

We use weak lensing data from the Hubble Space Telescope COSMOS survey to measure the second- and third-order moments of the cosmic shear field, estimated from about 450 000 galaxies with average redshift inline image.

We measure two- and three-point shear statistics using a tree-code, dividing the signal in E, B and mixed components. We present a detection of the third-order moment of the aperture mass statistic and verify that the measurement is robust against systematic errors caused by point spread function (PSF) residuals and by the intrinsic alignments between galaxies. The amplitude of the measured three-point cosmic shear signal is in very good agreement with the predictions for a 7-yr Wilkinson Microwave Anisotropy Probe (WMAP7) best-fitting model, whereas the amplitudes of potential systematics are consistent with zero.

We make use of three sets of large Lambda cold dark matter (ΛCDM) simulations to test the accuracy of the cosmological predictions and to estimate the influence of the cosmology-dependent covariance.

We perform a likelihood analysis using the measurement of M3ap〉 (θ) and find that the Ωm−σ8 degeneracy direction is well fitted by the relation: σ8m/0.30)0.49= 0.78+0.11−0.26 which is in good agreement with the best-fitting relation obtained by using the measurement of M2ap〉 (θ): σ8m/0.30)0.67= 0.70+0.11−0.14.

We present the first measurement of the more generalized three-point shear statistic M3ap〉 (θ1, θ2, θ3) and find a very good agreement with the WMAP7 best-fitting cosmology. The cosmological interpretation of M3ap〉 (θ1, θ2, θ3) gives σ8m/0.30)0.46= 0.69+0.08−0.14. Furthermore, the combined likelihood analysis of M3ap〉 (θ1, θ2, θ3) and M2ap〉 (θ) improves the accuracy of the cosmological constraints to σ8m/0.30)0.50= 0.69+0.07−0.12, showing the high potential of this combination of measurements to infer cosmological constraints.

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