SIMULATIONS OF WIDE-FIELD WEAK LENSING SURVEYS. I. BASIC STATISTICS AND NON-GAUSSIAN EFFECTS

By Masanori Sato, T. Hamana, Ryuichi Takahashi, M. Takada, Naoki Yoshida, Takahiko Matsubara, N. Sugiyama. 2009

151 citations recorded by the source corpus.

We study the lensing convergence power spectrum and its covariance for a standard ΛCDM cosmology. We run 400 cosmological N-body simulations and use the outputs to perform a total of 1000 independent ray-tracing simulations. We compare the simulation results with analytic model predictions. The semianalytic model based on Smith et al. fitting formula underestimates the convergence power by ∼ 30% at arcmin angular scales. For the convergence power spectrum covariance, the halo model reproduces the simulation results remarkably well over a wide range of angular scales and source redshifts. The dominant contribution at small angular scales comes from the sample variance due to the number fluctuations of halos in a finite survey volume. The signal-to-noise ratio for the convergence power spectrum is degraded by the non-Gaussian covariances by up to a factor of 5 for a weak lensing survey to zs ∼ 1. The probability distribution of the convergence power spectrum estimators, among the realizations, is well approximated by a χ2 distribution with broadened variance given by the non-Gaussian covariance, but has a larger positive tail. The skewness and kurtosis have non-negligible values especially for a shallow survey. We argue that a prior knowledge on the full distribution may be needed to obtain an unbiased estimate on the ensemble-averaged band power at each angular scale from a finite volume survey.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d11f089312d7e9f2c4d815d3051cd06d1defd859

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

REVISING THE HALOFIT MODEL FOR THE NONLINEAR MATTER POWER SPECTRUM (2012, methodology): “…that the model fails to reproduce recent high-resolution N-body simulation results at small scales (e.g., Springel et al. 2005; Hilbert et al. 2009; Sato et al. 2009; Boylan-Kolchin et al. 2009; Takahashi et al. 2011a; Kiessling et al. 2011; Valageas & Nishimichi 2011a, 2011b; Harnois-Deraps et…”
CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing (2012, methodology): “Following Sato et al. (2009), we estimate the HSV to dominate the CFHTLenS total covariance at ≈ 2 × 103, corresponding to 5 arcmin which is the Clone covariance regime.”
Putting the precision in precision cosmology: How accurate should your data covariance matrix be? (2012, methodology): “For example, Takahashi et al. (2009) have tested nonlinear modelling of the galaxy clustering data covariance matrix on a suite of 5000 simulations, while Sato et al. (2009) have tested nonlinear estimates of the weak lensing covariance on simulations.”
Detailed cluster lensing profiles at large radii and the impact on cluster weak lensing studies (2011, methodology): “In order to study the detailed radial profiles of lensing signals around massive haloes, we employ a large set of ray-tracing simulations presented by Sato et al. (2009).”
COSMOLIKE - cosmological likelihood analyses for photometric galaxy surveys (2016, background): “However, covariance terms that arise from these higher-order moments can significantly impact error bars (Sato et al. 2009); these terms were included in the analyses of Eifler et al. (2014); Takada & Spergel (2014); Park et al. (2015) all of which vary in terms of the probes considered.”
Constraining primordial non-Gaussianity with future galaxy surveys (2011, background): “More extended calculations have shown that extra terms arise, due to the connected matter trispectrum and also to the coupling of large-scale modes which are outside the volume of the survey (Sato et al. 2009; Takada & Jain 2009).”
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data (2018, methodology): “In a finite sky area, mode fluctuations whose scales are larger than the survey area generate excess covariance in the cosmic shear power spectra (Takada & Bridle 2007; Sato et al. 2009).”