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

Abstract

We derived constraints on cosmological parameters using weak lensing peak statistics measured on the $\sim130~{\rm deg}^2$ 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 $Λ$CDM model with only $(Ω_{\rm m}, σ_8)$ as free parameters, we constrained the parameters of the following relation $Σ_8=σ_8(Ω_{\rm m}/0.27)^α$ to be: $Σ_8=0.82 \pm 0.03 $ and $α=0.43\pm 0.02$. 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 $(Ω_{\rm m}, σ_8)$ are fully consistent with the ones from either WMAP9 or Planck. From the weak lensing peak abundances alone, we obtained marginalised mean values of $Ω_{\rm m}=0.38^{+0.27}_{-0.24}$ and $σ_8=0.81\pm 0.26$. 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.