Cosmological Constraints From Weak Lensing Peak Statistics With CFHT Stripe 82 Survey

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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 (CS82). 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 ΛCDM model with only (Ω m, σ₈) as free parameters, we constrained the parameters of the following relation Σ₈=σ₈(Ω m/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 (Ω m, σ₈) are fully consistent with the ones from either WMAP9 or Planck. From the weak lensing peak abundances alone, we obtained marginalised mean values of Ω 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 halos simultaneously with cosmological parameters.