Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments

Abstract

We present 108 full-sky gravitational lensing simulation data sets generated by performing multiplelens plane ray-tracing through high-resolution cosmological N -body simulations. The data sets include full-sky convergence and shear maps from redshifts z = 0.05 to 5.3 at intervals of 150 h −1 Mpc comoving radial distance (corresponding to a redshift interval of ∆z ≃ 0.05 at the nearby universe), enabling the construction of a mock shear catalog for an arbitrary source distribution up to z = 5.3. The dark matter halos are identified from the same N -body simulations with enough mass resolution to resolve the host halos of the Sloan Digital Sky Survey (SDSS) CMASS and luminous red galaxies (LRGs). Angular positions and redshifts of the halos are provided by a ray-tracing calculation, enabling the creation of a mock halo catalog to be used for galaxy-galaxy and cluster-galaxy lensing. The simulation also yields maps of gravitational lensing deflections for a source redshift at the last scattering surface, and we provide 108 realizations of lensed cosmic microwave background (CMB) maps in which the post-Born corrections caused by multiple light scattering are included. We present basic statistics of the simulation data, including the angular power spectra of cosmic shear, CMB temperature and polarization anisotropies, galaxy-galaxy lensing signals for halos, and their covariances. The angular power spectra of the cosmic shear and CMB anisotropies agree with theoretical predictions within 5% up to ℓ = 3000 (or at an angular scale θ > 0.5 arcmin). The simulation data sets are generated primarily for the ongoing Subaru Hyper Suprime-Cam survey, but are freely available for download at

Two- and three-dimensional wide-field weak lensing mass maps from the Hyper Suprime-Cam Subaru Strategic Program S16A data

“…The cosmological model is from the best-fit result of the Wilkinson Microwave Anisotropy Probe nine year data (Hinshaw et al 2013) with ΩM = 0.279, Ω b = 0.046, ΩΛ = 0.721, h = 0.7, ns = 0.97, and σ8 = 0.82. Takahashi et al (2017) created all-sky weak lensing maps at 38 source redshift slices from z = 0.05 to 5.3, which are stored in a HEALPix format (Górski et al 2005). Although there are realizations with different angular resolutions, we use a low resolution version with NSIDE equal to 4096, which roughly corresponds to a pixel size of ∼ 1 arcmin.…”

“…For weak lensing, we take all-sky weak lensing maps presented in Takahashi et al (2017). The cosmological model is from the best-fit result of the Wilkinson Microwave Anisotropy Probe nine year data (Hinshaw et al 2013) with ΩM = 0.279, Ω b = 0.046, ΩΛ = 0.721, h = 0.7, ns = 0.97, and σ8 = 0.82.…”

Probing supervoids with weak lensing

“…The details of the simulations are described in Section 2 in Takahashi et al (2017). To carry out N-body simulations, they ran the parallel Tree-Particle Mesh code, Gadget2 (Springel et al 2005) with 2048 3 particles.…”

Post-Born corrections to the one-point statistics of (CMB) lensing convergence obtained via large deviation theory

“…The ray-tracing scheme was then applied in the same fashion as for the other lensing maps. Note that although the density field at epochs beyond redshift 7 is very close to the linear regime for the scales we consider, the method used by Takahashi et al (2017) inevitably introduces some inaccuracies in the non-linearities of the density field and a fortiori the convergence field. However, we checked using tree-order perturbation theory that the error induced on the non linear convergence skewness at redshift 1100 and opening angle of 10 arcmin is only ∼ 2%.…”