Cosmology constraints from the weak lensing peak counts and the power spectrum in CFHTLenS data
Abstract
Lensing peaks have been proposed as a useful statistic, containing cosmological information from nonGaussianities that is inaccessible from traditional twopoint statistics such as the power spectrum or twopoint correlation functions. Here we examine constraints on cosmological parameters from weak lensing peak counts, using the publicly available data from the 154 deg^{2} CFHTLenS survey. We utilize a new suite of raytracing Nbody simulations on a grid of 91 cosmological models covering broad ranges of the three parameters Ω_{m}, σ_{8}, and w , and replicating the Galaxy sky positions, redshifts, and shape noise in the CFHTLenS observations. We then build an emulator that interpolates the power spectrum and the peak counts to an accuracy of ≤5 %, and compute the likelihood in the threedimensional parameter space (Ω_{m}, σ_{8}, w ) from both observables. We find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined. Neither observable can constrain w without external data. When the power spectrum and peak counts are combined, the area of the error "banana" in the (Ω_{m}, σ_{8}) plane reduces by a factor of ≈2 , compared to using the power spectrum alone. For a flat Λ cold dark matter model, combining both statistics, we obtain the constraint σ_{8}(Ω_{m}/0.27 )^{0.63}=0.85_{0.03}^{+0.03} .
 Publication:

Physical Review D
 Pub Date:
 March 2015
 DOI:
 10.1103/PhysRevD.91.063507
 arXiv:
 arXiv:1412.0757
 Bibcode:
 2015PhRvD..91f3507L
 Keywords:

 98.80.k;
 95.30.Sf;
 95.36.+x;
 98.62.Sb;
 Cosmology;
 Relativity and gravitation;
 Dark energy;
 Gravitational lenses and luminous arcs;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 15 pages, 14 figures. The manuscript has been revised and matches published version