Shear calibration biases in weak-lensing surveys

By C. Hirata, Uros Seljak. 2003

301 citations recorded by the source corpus.

We investigate biases induced by the conversion between the observed image shape and shear distortion in current weak-lensing analysis methods. Such overall calibration biases cannot be detected by the standard tests such as E/B decomposition or calibration with stars. We find that the non-Gaussianity of the point spread function has a significant effect and can lead to an error of up to 15 per cent on the linear amplitude of fluctuations σ 8 , depending on the method of analysis. This could explain some of the discrepancies seen in recent amplitude determinations from weak lensing. Using an elliptical Laguerre expansion method we develop a re-Gaussianization method that reduces the error to a calibration error of the order of 1 per cent, even for poorly resolved galaxies. We also discuss a new type of shear selection bias, which results in up to roughly an 8 per cent underestimation of the signal. It is expected to scale with redshift, inducing errors in the growth factor extraction if not properly corrected for. Understanding and correcting fear such effects is crucial if weak lensing is to become a high-precision probe of cosmology.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/412494830d5a64c86952ff1dcff8c5002edff0e2

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Citations in the corpus

Weak Lensing Measurement of the Mass--Richness Relation of SDSS redMaPPer Clusters (2016, methodology): “The images were analyzed with the re-Gaussianization algorithm1 (Hirata & Seljak 2003), which calculates adaptive second-order moments for the galaxy and point-spread function (PSF) by fitting elliptical Gaussians to the images, and then combines these moments and a correction for low-order…”
The skewness of the aperture mass statistic (2003, methodology): “We have also corrected the error pointed out by Hirata & Seljak (2003) in our dilution correction formula.”
The first-year shear catalog of the Subaru Hyper Suprime-Cam Subaru Strategic Program Survey (2017, methodology): “In the course of the re-Gaussianization PSFcorrection method, corrections are applied to account for dilution of the observed shape by the PSF, including the nonGaussianity of both the PSF and the galaxy surface brightness profiles (Hirata & Seljak 2003).”
Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17 (2007, methodology): “The method has been extensively tested in Bernstein & Jarvis (2002), Hirata & Seljak (2003), Wittman et al. (2003), Park et al. (2004), Margoniner et al. (2005), Jarvis et al. (2003), etc.”
Density profiles of galaxy groups and clusters from SDSS galaxy–galaxy weak lensing (2006, methodology): “…30 million galaxies from the SDSS imaging data with r-band model magnitude brighter than 21.8, with shape measurements obtained using the REGLENS pipeline, including PSF correction done via reGaussianization (Hirata & Seljak 2003) and with cuts designed to avoid various shear calibration biases.”
Cosmological parameter constraints from galaxy-galaxy lensing and galaxy clustering with the SDSS DR7 (2012, methodology): “In the course of the re-Gaussianization PSFcorrection method, corrections are applied to account for non-Gaussianity of both the PSF and the galaxy surface brightness profiles (Hirata & Seljak 2003).”
The Hyper Suprime-Cam Software Pipeline (2017, methodology): “In addition to adaptive moments, the HSM algorithms also include several approaches to estimating PSF-corrected ellipticities for the purpose of estimating shear due to weak gravitational lensing.”
The DES Science Verification weak lensing shear catalogues (2015, methodology): “To assess the quality of the PSF interpolation, we first examined the differences between the measured shapes (using the HSM algorithm again) of actual stars on the image and the corresponding values for the PSFEX model at the locations of these stars.”
Systematic errors in weak lensing: application to SDSS galaxy-galaxy weak lensing (2005, methodology): “…due to this effect for the less well-resolved galaxies, the reGaussianization method only has a few per cent shear calibration uncertainty (Hirata & Seljak 2003) even for the lower limit C© 2005 RAS, MNRAS 361, 1287–1322 Downloaded from…”
Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data (2018, methodology): “The shapes of galaxies are estimated on the i-band coadded images using the re-Gaussianization PSF correction method (Hirata & Seljak 2003).”
Observational probes of cosmic acceleration (2012, methodology): “Pan-STARRS and DES will both carry out large area, multi-band imaging surveys that go a factor of ten or more deeper (in flux) than the SDSS imaging survey (Abazajian et al., 2009), using, respectively, a 1.4-Gigapixel camera on the 1.8-m PS1 telescope on Haleakala in Hawaii and a 0.5-Gigapixel came”
Mapping stellar content to dark matter haloes using galaxy clustering and galaxy–galaxy lensing in the SDSS DR7 (2015, methodology): “…a catalogue of background galaxies (Reyes et al. 2012) with a number density of 1.2 arcmin−2 with weak lensing shears estimated using the re-Gaussianization method (Hirata & Seljak 2003) and photometric redshifts from Zurich Extragalactic Bayesian Redshift Analyzer (ZEBRA, Feldmann et al. 2006).”
The WiggleZ Dark Energy Survey: Direct constraints on blue galaxy intrinsic alignments at intermediate redshifts (2009, methodology): “We refer the interested reader to Hirata & Seljak (2003) for an outline of the PSF correction technique (reGaussianization) and to Mandelbaum et al. (2005) for all details of the shape measurement.”
Constraints on intrinsic alignment contamination of weak lensing surveys using the MegaZ-LRG sample (2010, methodology): “We refer the interested reader to Hirata & Seljak (2003) for an outline of the PSF correction technique (re-Gaussianisation) and to Mandelbaum et al. (2005) for all details of the shape measurement.”
Detection of large-scale intrinsic ellipticity—density correlation from the Sloan Digital Sky Survey and implications for weak lensing surveys (2005, methodology): “…PSF; Mandelbaum et al. (2005a) uses the PSF maps obtained from stellar images by the psp pipeline (Lupton et al. 2001), and corrects for these using the re-Gaussianization technique of Hirata & Seljak (2003a), which includes corrections for non-Gaussianity of both the galaxy profile and the PSF.”
Effects of Photometric Redshift Uncertainties on Weak-Lensing Tomography (2005, background): “Such studies have stimulated work on how to improve the PSF reconstruction (Jarvis & Jain 2004), estimate shear from noisy maps (Bernstein & Jarvis 2002; Hirata & Seljak 2003; Hoekstra 2004), and protect against the small-scale biases in the power spectrum (Huterer & White 2005).”