Emulating the CFHTLenS weak lensing data: Cosmological constraints from moments and Minkowski functionals
Abstract
Weak gravitational lensing is a powerful cosmological probe, with nonGaussian features potentially containing the majority of the information. We examine constraints on the parameter triplet (Ω_{m},w ,σ_{8}) from nonGaussian features of the weak lensing convergence field, including a set of moments (up to fourth order) and Minkowski functionals, using publicly available data from the 154 deg^{2} CFHTLenS survey. We utilize a suite of raytracing Nbody simulations spanning 91 points in (Ω_{m},w ,σ_{8}) parameter space, replicating the galaxy sky positions, redshifts and shape noise in the CFHTLenS catalogs. We then build an emulator that interpolates the simulated descriptors as a function of (Ω_{m},w ,σ_{8}), and use it to compute the likelihood function and parameter constraints. We employ a principal component analysis to reduce dimensionality and to help stabilize the constraints with respect to the number of bins used to construct each statistic. Using the full set of statistics, we find Σ_{8}≡σ_{8}(Ω_{m}/0.27 )^{0.55}=0.75 ±0.04 (68% C.L.), in agreement with previous values. We find that constraints on the (Ω_{m},σ_{8}) doublet from the Minkowski functionals suffer a strong bias. However, highorder moments break the (Ω_{m},σ_{8}) degeneracy and provide a tight constraint on these parameters with no apparent bias. The main contribution comes from quartic moments of derivatives.
 Publication:

Physical Review D
 Pub Date:
 May 2015
 DOI:
 10.1103/PhysRevD.91.103511
 arXiv:
 arXiv:1503.06214
 Bibcode:
 2015PhRvD..91j3511P
 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:
 17 pages, 10 figures, 4 tables