Bayesian galaxy shape measurement for weak lensing surveys – III. Application to the Canada–France–Hawaii Telescope Lensing Survey

2012/10/30 by L. Miller, Catherine Heymans, C. Heymans +26 · 449 citations
Computer Science · Physics and Astronomy · #Adaptive optics and wavefront sensing #Advanced Vision and Imaging #Astronomy #Astrophysics #Distortion (music) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Optics #Physics #Point spread function #Redshift #Weak gravitational lensing #astro-ph.CO

paper · pdf · doi:10.1093/mnras/sts454

published in Monthly Notices of the Royal Astronomical Society 429(4), 2858-2880 (Oxford University Press) · 24 pages, submitted to MNRAS. All CFHTLenS data products (image pixel data and lensing/photo-z catalogues) are publicly released to the community via CADC on the 1st of November 2012. Please visit the CFHTLenS site http://www.cfhtlens.org for further information

arxiv created 2012/10/30 · openalex publication_date 2013/01/14 · arxiv updated 2013/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

A likelihood-based method for measuring weak gravitational lensing shear in deep galaxy surveys is described and applied to the Canada–France–Hawaii Telescope (CFHT) Lensing Survey (CFHTLenS). CFHTLenS comprises 154 deg2 of multi-colour optical data from the CFHT Legacy Survey, with lensing measurements being made in the i′ band to a depth i′AB < 24.7, for galaxies with signal-to-noise ratio νSN ≳ 10. The method is based on the lensfit algorithm described in earlier papers, but here we describe a full analysis pipeline that takes into account the properties of real surveys. The method creates pixel-based models of the varying point spread function (PSF) in individual image exposures. It fits PSF-convolved two-component (disc plus bulge) models to measure the ellipticity of each galaxy, with Bayesian marginalization over model nuisance parameters of galaxy position, size, brightness and bulge fraction. The method allows optimal joint measurement of multiple, dithered image exposures, taking into account imaging distortion and the alignment of the multiple measurements. We discuss the effects of noise bias on the likelihood distribution of galaxy ellipticity. Two sets of image simulations that mirror the observed properties of CFHTLenS have been created to establish the method's accuracy and to derive an empirical correction for the effects of noise bias.

Citations

• Canada-France Redshift Survey. XI. Morphology of High-Redshift Field Galaxies from High-Resolution Ground-based Imaging
• CFHTLenS: The Canada-France-Hawaii Telescope Lensing Survey
• Bayesian galaxy shape measurement for weak lensing surveys - II. Application to simulations
• Evidence of the accelerated expansion of the Universe from weak lensing tomography with COSMOS
• Point spread function calibration requirements for dark energy from cosmic shear

Cited by

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• CFHTLenS: Galaxy bias as function of scale, stellar mass, and colour
• 3D cosmic shear: cosmology from CFHTLenS
• Unveiling the Intrinsic Alignment of Galaxies with Self-calibration and DECaLS DR3 Data
• Tightening weak lensing constraints on the ellipticity of galaxy-scale dark matter haloes
• THE WEAK LENSING SIGNAL AND THE CLUSTERING OF BOSS GALAXIES. II. ASTROPHYSICAL AND COSMOLOGICAL CONSTRAINTS
• CFHTLenS and RCSLenS cross-correlation with Planck lensing detected in fourier and configuration space
• Origin of weak lensing convergence peaks
• KiDS-450: cosmological constraints from weak-lensing peak statistics – II: Inference from shear peaks using N-body simulations
• MASS–CONCENTRATION RELATION OF CLUSTERS OF GALAXIES FROM CFHTLenS
• Bayesian weak lensing tomography: Reconstructing the 3D large-scale distribution of matter with a lognormal prior
• Weak-lensing shear estimates with general adaptive moments, and studies of bias by pixellation, PSF distortions, and noise
• AMICO galaxy clusters in KiDS-DR3
• Testing gravity on large scales by combining weak lensing with galaxy clustering using CFHTLenS and BOSS CMASS
• Defining a weak lensing experiment in space
• The XXL Survey
• Cosmic shear measurements with Dark Energy Survey Science Verification data
• CFHTLenS: the environmental dependence of galaxy halo masses from weak lensing
• GAMA + KiDS: empirical correlations between halo mass and other galaxy properties near the knee of the stellar-to-halo mass relation
• Cosmological simulations for combined-probe analyses: covariance and neighbour-exclusion bias
• Radio weak lensing shear measurement in the visibility domain – II. Source extraction
• The effects of calibration on the bias of shear measurements
• Constraining Dark Energy with Stacked Concave Lenses
• CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES

Related

• Bayesian Galaxy Shape Measurement for Weak Lensing Surveys -I. Methodology and a Fast Fitting Algorithm
• Bayesian galaxy shape measurement for weak lensing surveys - II. Application to simulations
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• Problems using ratios of galaxy shape moments on requirements for weak lensing surveys