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Current and future imaging surveys will measure cosmic shear with a statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 J. E. Meyers , P. R. Burchat

Current and future imaging surveys will measure cosmic shear with statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We use analytic and…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-15 Joshua E. Meyers , Patricia R. Burchat

Weak gravitational lensing (WL) is a key cosmological probe that requires precise measurement of galaxy images to infer shape distortions, or shear, and constrain cosmology. Accurate estimation of the Point Spread Function (PSF) is crucial…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-28 Federico Berlfein , Rachel Mandelbaum , Xiangchong Li , Tianqing Zhang , Scott Dodelson , Katarina Markovic

Cosmic shear requires high precision measurement of galaxy shapes in the presence of the observational Point Spread Function (PSF) that smears out the image. The PSF must therefore be known for each galaxy to a high accuracy. However, for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 E. S. Cypriano , A. Amara , L. M. Voigt , S. L. Bridle , F. B. Abdalla , A. Refregier , M. Seiffert , J. Rhodes

Weak gravitational lensing is one of the most powerful tools for cosmology, while subject to challenges in quantifying subtle systematic biases. The Point Spread Function (PSF) can cause biases in weak lensing shear inference when the PSF…

Instrumentation and Methods for Astrophysics · Physics 2021-12-13 Tianqing Zhang , Rachel Mandelbaum , The LSST Dark Energy Science Collaboration

Weak gravitational lensing requires precise measurements of galaxy shapes and therefore an accurate knowledge of the PSF model. The latter can be a source of systematics that affect the shear two-point correlation function. A key stake of…

Aims:Calibrating the point spread function (PSF) is a fundamental part of weak gravitational lensing analyses. Even with corrected galaxy images, imperfect calibrations can introduce biases. We propose an analytical framework for…

Galaxy color gradients - i.e., spectral energy distributions that vary across the galaxy profile - will impact galaxy shape measurements when the modeled point spread function (PSF) corresponds to that for a galaxy with spatially uniform…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-11 Sowmya Kamath , Joshua E. Meyers , Patricia R. Burchat

Cosmic shear has been identified as the method with the most potential to constrain dark energy. To capitalise on this potential it is necessary to measure galaxy shapes with great accuracy, which in turn requires a detailed model for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 L. M. Voigt , S. L. Bridle , A. Amara , M. Cropper , T. D. Kitching , R. Massey , J. Rhodes , T. Schrabback

Accurate shape measurements are essential to infer cosmological parameters from large area weak gravitational lensing studies. The compact diffraction-limited point-spread function (PSF) in space-based observations is greatly beneficial,…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-20 Xinzhong Er , Henk Hoekstra , Tim Schrabback , Vincenzo F. Cardone , Roberto Scaramella , Roberto Maoli , Martina Vicinanza , Bryan Gillis , Jason Rhodes

Weak gravitational lensing, or weak lensing, is one of the most powerful probes for dark matter and dark energy science, although it faces increasing challenges in controlling systematic uncertainties as \edit{the statistical errors become…

Wavelength-dependent point spread functions (PSFs) violate an implicit assumption in current galaxy shape measurement algorithms that deconvolve the PSF measured from stars (which have stellar spectral energy distributions (SEDs)) from…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Joshua E. Meyers , Patricia R. Burchat

We have developed a new technique for weak lensing analysis, with which the effect of the point spread function (PSF) on small galaxy images can be corrected for accurately. Rather than relying on weighted second moments of detected images,…

Astrophysics · Physics 2016-08-30 Konrad Kuijken

Weak lensing by large-scale structure is an invaluable cosmological tool given that most of the energy density of the concordance cosmology is invisible. Several large ground-based imaging surveys will attempt to measure this effect over…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Eric M. Huff , Christopher M. Hirata , Rachel Mandelbaum , David Schlegel , Uros Seljak , Robert H. Lupton

Accurate reconstruction of the spatial distributions of the Point Spread Function (PSF) is crucial for high precision cosmic shear measurements. Nevertheless, current methods are not good at recovering the PSF fluctuations of high spatial…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-12 Tianhuan Lu , Jun Zhang , Fuyu Dong , Yingke Li , Dezi Liu , Liping Fu , Guoliang Li , Zuhui Fan

The accurate modelling of the Point Spread Function (PSF) is of paramount importance in astronomical observations, as it allows for the correction of distortions and blurring caused by the telescope and atmosphere. PSF modelling is crucial…

Instrumentation and Methods for Astrophysics · Physics 2023-09-25 Tobias Liaudat , Jean-Luc Starck , Martin Kilbinger

Telescope Point Spread Function (PSF) quality is critical for realising the potential of cosmic weak lensing observations to constrain dark energy and test General Relativity. In this paper we use quantitative weak gravitational lensing…

The convolution of galaxy images by the point-spread function (PSF) is the dominant source of bias for weak gravitational lensing studies, and an accurate estimate of the PSF is required to obtain unbiased shape measurements. The PSF…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Martin Eriksen , Henk Hoekstra

Chromatic point-spread-function (PSF) effects arise from differences between the spectral energy distributions (SEDs) of stars, used to model the PSF, and galaxies, used to measure shape distortions due to weak gravitational lensing, or…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-18 Federico Berlfein , Rachel Mandelbaum , Jiachuan Xu , Tianqing Zhang

The spatial variation of the colour of a galaxy may introduce a bias in the measurement of its shape if the PSF profile depends on wavelength. We study how this bias depends on the properties of the PSF and the galaxies themselves. The bias…

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