The impact of non‐Gaussian errors on weak lensing surveys

By M. Takada, Bhuvnesh Jain Ipmu, U. Tokyo, U. Penn. 2008

141 citations recorded by the source corpus.

The weak lensing power spectrum carries cosmological information via its dependence on the growth of structure and on geometric factors. Since much of the cosmological information comes from scales affected by non-linear clustering, measurements of the lensing power spectrum can be degraded by non-Gaussian covariances. Recently, there have been conflicting studies about the level of this degradation. We use the halo model to estimate it and include new contributions related to the finite size of lensing surveys, following Rimes and Hamilton's study of three-dimensional simulations. We find that non-Gaussian correlations between different multipoles can degrade the cumulative signal-to-noise ratio (S/N) for the power spectrum amplitude by up to a factor of 2 (or 5 for a worst-case model that exceeds current N-body simulation predictions). However, using an eight-parameter Fisher analysis, we find that the marginalized errors on individual parameters are degraded by less than 10 per cent (or 20 per cent for the worst-case model). The smaller degradation in parameter accuracy is primarily because: individual parameters in a high-dimensional parameter space are degraded much less than the volume of the full Fisher ellipsoid; lensing involves projections along the line of sight, which reduce the non-Gaussian effect; some of the cosmological information comes from geometric factors which are not degraded at all. We contrast our findings with those of Lee and Pen who suggested a much larger degradation in information content. Finally, our results give a useful guide for exploring survey design by giving the cosmological information returns for varying survey area, depth and the level of some systematic errors.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/65d385620305547483a8d993a602c3c8abc068ea

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Citations in the corpus

SIMULATIONS OF WIDE-FIELD WEAK LENSING SURVEYS. I. BASIC STATISTICS AND NON-GAUSSIAN EFFECTS (2009, methodology): “…non-Gaussian errors are dominant over the shot noise due to intrinsic galaxy shapes, therefore the effect needs to be properly taken into account to obtain unbiased, secure extraction of cosmological parameters from the measured power spectrum (see Takada & Jain (2009) for the similar discussion).”
Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data (2019, methodology): “In the case of the TPCF, the halo-modelbased analytic covariance matrix was formulated (Cooray & Hu 2001; Takada & Jain 2009; Takada & Hu 2013).”
CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing (2012, background): “Neglecting those can yield overly optimistic cosmological constraints (Semboloni et al. 2007, hereafter S07; Takada & Jain 2009; Hilbert, Hartlap & Schneider 2011).”
Putting the precision in precision cosmology: How accurate should your data covariance matrix be? (2012, methodology): “…model has been used to estimate the covariance matrix for the matter and weak lensing power spectra (e.g., Cooray & Hu, 2001; Takada & Bridle, 2007; Takada & Jain 2009; Kayo et al., 2012), while estimation of the data covariance matrix for a lognormal field (e.g., Hilbert, et al., 2011) seems to…”
Quantifying the effect of baryon physics on weak lensing tomography (2011, background): “As a consequence, the value of the variance is increased (Semboloni et al. 2007; Takada & Jain 2009; Pielorz et al. 2010).”
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).”
COSMOLIKE - cosmological likelihood analyses for photometric galaxy surveys (2016, background): “…l′/χ,−l′/χ ; z(χ )), (A3) where we approximate the ABCD trispectrum as the sum of the linearly biased (2 + 3 + 4)-halo matter trispectrum (see e.g. Cooray & Sheth 2002; Takada & Jain 2009, for details), and a probe-specific 1-halo trispectrum: T ijkl ABCD ( k, −k, k′, −k′; z) ≈…”
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data (2018, methodology): “The excess covariance due to super-sample modes has also been studied (Takada & Bridle 2007; Takada & Jain 2009; Takada & Hu 2013) and tested using ray-tracing simulations (Sato et al. 2009).”