Abstract
We derived constraints on cosmological parameters using weak lensing peak statistics measured on the ∼ 130 deg2 of the Canada–France–Hawaii Telescope Stripe 82 Survey. This analysis demonstrates the feasibility of using peak statistics in cosmological studies. For our measurements, we considered peaks with signal-to-noise ratio in the range of ν = [3, 6]. For a flat Λ cold dark matter model with only (Ωm, σ8) as free parameters, we constrained the parameters of the following relation Σ8 = σ8(Ωm/0.27)α to be Σ8 = 0.82 ± 0.03 and α = 0.43 ± 0.02. The α value found is considerably smaller than the one measured in two-point and three-point cosmic shear correlation analyses, showing a significant complement of peak statistics to standard weak lensing cosmological studies. The derived constraints on (Ωm, σ8) are fully consistent with the ones from either WMAP9 or Planck. From the weak lensing peak abundances alone, we obtained marginalized mean values of |$\Omega _{\rm m}=0.38^{+0.27}_{-0.24}$| and σ8 = 0.81 ± 0.26. Finally, we also explored the potential of using weak lensing peak statistics to constrain the mass–concentration relation of dark matter haloes simultaneously with cosmological parameters.
Highlights
Large-scale structures in the Universe perturb the propagation of light rays from background sources causing small shape distortions and luminosity changes for their observed images (e.g. Bartelmann& Schneider 2001)
As this work was being completed, we became aware of the study by LPH2015. They analysed the cosmological application of weak lensing peak statistics using CFHTLenS data. Their studies are based on interpolations from a suite of simulation templates on a grid of 91 cosmological models in the parameter space of ( m, σ 8, w),where m, σ 8 and w are, respectively, the dimensionless matter density of the Universe, the amplitude of the extrapolated linear matter density fluctuations smoothed over a top-hat scale of 8h−1Mpc, and the equation of state of dark energy
To see if the constraints, the degeneracy direction between ( m, σ 8), can be affected significantly by allowing more free cosmological parameters, we study the dependence of the peak abundances on ( m, σ 8, b, ns, h) by calculating the derivatives with respect to these parameters using the model of F10
Summary
Large-scale structures in the Universe perturb the propagation of light rays from background sources causing small shape distortions and luminosity changes for their observed images Assuming Gaussian random fields for both the projected field of large-scale structures and the shape noise, Maturi et al (2010) proposed a theoretical model to calculate the number of contiguous areas above a given threshold in the filtered convergence field This is equivalent to the genus in Minkowski functionals. They analysed the cosmological application of weak lensing peak statistics using CFHTLenS data Their studies are based on interpolations from a suite of simulation templates on a grid of 91 cosmological models in the parameter space of ( m, σ 8, w) ,where m, σ 8 and w are, respectively, the dimensionless matter density of the Universe, the amplitude of the extrapolated linear matter density fluctuations smoothed over a top-hat scale of 8h−1Mpc, and the equation of state of dark energy.
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