Euclid: Nonparametric point spread function field recovery through interpolation on a graph Laplacian

Abstract

Context. Future weak lensing surveys, such as the Euclid mission, will attempt to measure the shapes of billions of galaxies in order to derive cosmological information. These surveys will attain very low levels of statistical error, and systematic errors must be extremely well controlled. In particular, the point spread function (PSF) must be estimated using stars in the field, and recovered with high accuracy. Aims. The aims of this paper are twofold. Firstly, we took steps toward a nonparametric method to address the issue of recovering the PSF field, namely that of finding the correct PSF at the position of any galaxy in the field, applicable to Euclid. Our approach relies solely on the data, as opposed to parametric methods that make use of our knowledge of the instrument. Secondly, we studied the impact of imperfect PSF models on the shape measurement of galaxies themselves, and whether common assumptions about this impact hold true in an Euclid scenario. Methods. We extended the recently proposed resolved components analysis approach, which performs super-resolution on a field of under-sampled observations of a spatially varying, image-valued function. We added a spatial interpolation component to the method, making it a true 2-dimensional PSF model. We compared our approach to PSFEx, then quantified the impact of PSF recovery errors on galaxy shape measurements through image simulations. Results. Our approach yields an improvement over PSFEx in terms of the PSF model and on observed galaxy shape errors, though it is at present far from reaching the required Euclid accuracy. We also find that the usual formalism used for the propagation of PSF model errors to weak lensing quantities no longer holds in the case of an Euclid-like PSF. In particular, different shape measurement approaches can react differently to the same PSF modeling errors.

19 pages, 19 figures. This version matches that published in A&A

References in corpus (31)

• Cosmology with cosmic shear observations: a review
• The Hyper Suprime-Cam Software Pipeline
• Bayesian Galaxy Shape Measurement for Weak Lensing Surveys - III. Application to the Canada-France-Hawaii Telescope Lensing Survey
• Gravitational Lensing Analysis of the Kilo Degree Survey
• The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses
• Generalized Forward-Backward Splitting
• Systematic errors in weak lensing: application to SDSS galaxy-galaxy weak lensing
• The first-year shear catalog of the Subaru Hyper Suprime-Cam SSP Survey
• Dark Energy Survey Year 1 Results: Weak Lensing Shape Catalogues
• Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation)
• The DES Science Verification Weak Lensing Shear Catalogues
• GREAT3 results I: systematic errors in shear estimation and the impact of real galaxy morphology
• The Third Gravitational Lensing Accuracy Testing (GREAT3) Challenge Handbook
• PSF calibration requirements for dark energy from cosmic shear
• Defining a weak lensing experiment in space
• IM3SHAPE: A maximum-likelihood galaxy shear measurement code for cosmic gravitational lensing
• Wasserstein Dictionary Learning: Optimal Transport-based unsupervised non-linear dictionary learning
• A study of the sensitivity of shape measurements to the input parameters of weak lensing image simulations
• Interpolating point spread function anisotropy
• On the Probability Distributions of Ellipticity
• Weak gravitational lensing with DEIMOS
• Fast Point Spread Function Modeling with Deep Learning
• On the shear estimation bias induced by the spatial variation of colour across galaxy profiles
• Optimal Linear Image Combination
• Stellar classification from single-band imaging using machine learning
• Optimal PSF modeling for weak lensing: complexity and sparsity
• Exploring the brighter fatter effect with the Hyper Suprime-Cam
• Super-resolution method using sparse regularization for point-spread function recovery
• Implications of a wavelength dependent PSF for weak lensing measurements
• Constraint matrix factorization for space variant PSFs field restoration
• Detecting unresolved binary stars in Euclid VIS images

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• Multi-CCD Point Spread Function Modelling
• Rethinking data-driven point spread function modeling with a differentiable optical model
• Superresolution Reconstruction of Severely Undersampled Point-spread Functions Using Point-source Stacking and Deconvolution
• Impact of Point Spread Function Higher Moments Error on Weak Gravitational Lensing II: A Comprehensive Study
• Impact of PSF misestimation and galaxy population bias on precision shear measurement using a CNN
• A review on fundamental bounds and estimators for photometry and astrometry of celestial point sources using array detectors, from first principles
• Impact of Point Spread Function Higher Moments Error on Weak Gravitational Lensing