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We present a joint weak lensing and X-ray analysis of 4 deg$^2$ from the CFHTLS and XMM-LSS surveys. Our weak lensing analysis is the first analysis of a real survey using shapelets, a new generation weak lensing analysis method. We create…

Cosmic shear is a primary cosmological probe for several present and upcoming surveys investigating dark matter and dark energy, such as Euclid or WFIRST. The probe requires an extremely accurate measurement of the shapes of millions of…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-04 Malte Tewes , Thibault Kuntzer , Reiko Nakajima , Frédéric Courbin , Hendrik Hildebrandt , Tim Schrabback

In this paper, we investigate the impact of higher-order distortions on the precise measurement of weak gravitational lensing shear and flexion. We begin by defining generalized higher-order distortions and outlining methods for measuring…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Yuki Okura , Toshifumi Futamase

We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-27 Chris Clarkson

Weak-lensing shear estimates show a troublesome dependence on the apparent brightness of the galaxies used to measure the ellipticity: In several studies, the amplitude of the inferred shear falls sharply with decreasing source…

Instrumentation and Methods for Astrophysics · Physics 2012-11-26 Peter Melchior , Massimo Viola

We update the publicly available weak lensing shear measurement algorithm pyRRG for the James Webb Space Telescope, and apply it to UNCOVER DR1 imaging of galaxy cluster Abell 2744. At short wavelengths (< 2.5$\mu$m), shear measurements are…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-31 David R. Harvey , Richard Massey

Measurements of the shear induced by weak gravitational lensing around galaxy cluster lines of sight are the gold standard for calibrating cluster observable-mass relations, thereby enabling a robust and precise inference of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-26 S. Bocquet , A. Fumagalli , C. T. Davies , K. Dolag , S. Grandis , J. J. Mohr

We investigate the impact of higher-order gravitational lens properties and properties of the background source on our approach to directly infer local lens properties from observables in multiple images of strong gravitationally lensed…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-28 Jenny Wagner

Weak lensing statistics is typically measured as weighted sum of shear estimators or their products (shear-shear correlation). The weighting schemes are designed in the hope of minimizing the statistical error without introducing systematic…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-24 Jun Zhang , Pengjie Zhang , Wentao Luo

Shear fields due to weak gravitational lensing have characteristic coherent patterns. We describe the topological defects in shear fields in terms of the curvature of the surface described by the lensing potential. A simple interpretation…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-02 Vincenzo Vitelli , Bhuvnesh Jain , Randall D. Kamien

We are developing a general, unified, and rigorous analytical framework for using gravitational lensing by compact objects to test different theories of gravity beyond the weak-deflection limit. In this paper we present the formalism for…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Charles R. Keeton , A. O. Petters

Context. The density split statistics in weak gravitational lensing analyses probes the correlation between regions of different (foreground) galaxy number densities and their weak lensing signal, measured by the shape distortion of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-21 Pierre Burger , Peter Schneider , Vasiliy Demchenko , Joachim Harnois-Deraps , Catherine Heymans , Hendrik Hildebrandt , Sandra Unruh

In weak gravitational lensing, weighted quadrupole moments of the brightness profile in galaxy images are a common way to estimate gravitational shear. We employ general adaptive moments (GLAM) to study causes of shear bias on a fundamental…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Patrick Simon , Peter Schneider

We report a detection of the coherent distortion of faint galaxies arising from gravitational lensing by foreground structures. This ``cosmic shear'' is potentially the most direct measure of the mass power spectrum, as it is unaffected by…

Astrophysics · Physics 2011-05-05 David Bacon , Alexandre Refregier , Richard Ellis

We examine the cosmological constraining power of future large-scale weak lensing surveys on the model of \emph{Euclid}, with particular reference to primordial non-Gaussianity. Our analysis considers several different estimators of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 C. Fedeli , M. Bartelmann , L. Moscardini

We discuss the galaxy-galaxy-mass three-point correlation function and show how to measure it with weak gravitational lensing. The method entails choosing a large of pairs of foreground lens galaxies and constructing a mean shear map with…

Astrophysics · Physics 2009-11-10 David E. Johnston

Galaxy-galaxy weak lensing provides a powerful means of measuring the average matter distribution around lens galaxies -- i.e., the galaxy bias relation. Properly accounting for the spin-2 nature of weak lensing distortions, we develop a…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-28 Taisei Terawaki , Masahiro Takada , Takanori Taniguchi

This review forms the Weak Lensing part of the Saas-Fee Advanced Course on Gravitational Lensing. It describes the basicsm applications and results of weak lensing. Contents: (1) Introduction (2) The principles of weak gravitational lensing…

Astrophysics · Physics 2009-11-11 Peter Schneider

Large scale correlations in the orientations of galaxies can result from alignments in their angular momentum vectors. These alignments arise from the tidal torques exerted on neighboring proto-galaxies by the smoothly varying shear field.…

Astrophysics · Physics 2009-07-09 Robert G. Crittenden , Priyamvada Natarajan , Ue-Li Pen , Tom Theuns