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We propose a new technique to directly measure the shapes of dark matter halos of galaxies using weak gravitational lensing. Extending the standard galaxy-galaxy lensing method, we show that the shape parameters of the mass distribution of…

Astrophysics · Physics 2009-10-31 Priyamvada Natarajan , Alexandre Refregier

Weak gravitational lensing provides a unique method to map directly the distribution of dark matter in the universe and to measure cosmological parameters. This cosmic-shear technique is based on the measurement of the weak distortions that…

Astrophysics · Physics 2008-11-26 Alexandre Refregier

Upcoming large astronomical surveys are expected to capture an unprecedented number of strong gravitational lensing systems. Deep learning is emerging as a promising practical tool for the detection and quantification of these galaxy-scale…

Weak gravitational lensing is a unique probe of the dark side of the universe: it provides a direct way to map the distribution of dark matter around galaxies, clusters of galaxies and on cosmological scales. Furthermore, the measurement of…

Astrophysics · Physics 2010-01-07 Henk Hoekstra , Bhuvnesh Jain

Traditional weak gravitational lensing shear estimators are carefully calibrated but struggle to fully capture realistic galaxy morphologies, point-spread-function (PSF) effects, blending, and noise in deep surveys, while blindly trained…

Instrumentation and Methods for Astrophysics · Physics 2026-03-20 Shurui Lin , Xiangchong Li , Ji Li , Shengcao Cao , Xin Liu , Yu-Xiong Wang

We introduce a novel method for weak-lensing measurements, which is based on a mathematically exact deconvolution of the moments of the apparent brightness distribution of galaxies from the telescope's PSF. No assumptions on the shape of…

Instrumentation and Methods for Astrophysics · Physics 2012-04-24 Peter Melchior , Massimo Viola , Björn Malte Schäfer , Matthias Bartelmann

We study the accuracy with which weak lensing measurements could be made from a future space-based survey, predicting the subsequent precisions of 3-dimensional dark matter maps, projected 2-dimensional dark matter maps, and mass-selected…

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. The advent of panoramic cameras on 4m class telescope has led to a first generation of…

Astrophysics · Physics 2019-10-23 Henk Hoekstra

It is now routine to measure the weak gravitational lensing shear signal from the mean ellipticity of distant galaxies. However, conversion between ellipticity and shear assumes local linearity of the lensing potential (ie that the spatial…

Astrophysics · Physics 2010-11-11 Richard Massey , David M. Goldberg

Weak gravitational lensing has the potential to constrain cosmological parameters to high precision. However, as shown by the Shear TEsting Programmes (STEP) and GRavitational lEnsing Accuracy Testing (GREAT) Challenges, measuring galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Tomasz Kacprzak , Joe Zuntz , Barnaby Rowe , Sarah Bridle , Alexandre Refregier , Adam Amara , Lisa Voigt , Michael Hirsch

We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data…

The weak distortions produced by gravitational lensing in the images of background galaxies provide a method to measure directly the distribution of mass in the universe. However this technique requires high precision measurements of the…

Astrophysics · Physics 2009-10-31 Jason Rhodes , Alexandre Refregier , Ed Groth

Weak lensing can be observed through a number of effects on the images of distant galaxies; their shapes are sheared, their sizes and fluxes (magnitudes) are magnified and their positions on the sky are modified by the lensing field. Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-12 Justin Alsing , Donnacha Kirk , Alan Heavens , Andrew Jaffe

Weak lensing measurements are entering a precision era to statistically map the distribution of matter in the universe. The most common measurement has been of the variance of the projected surface density of matter, which corresponds to…

Astrophysics · Physics 2009-11-07 Tong-Jie Zhang , Ue-Li Pen , Pengjie Zhang , John Dubinski

Evolution in the mass function of galaxy clusters sensitively traces both the expansion history of the Universe and cosmological structure formation. Robust cluster mass determinations are a key ingredient for a reliable measurement of this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Holger Israel , Thomas Erben , Thomas H. Reiprich , Alexey Vikhlinin , Craig L. Sarazin , Peter Schneider

Weak lensing applied to deep optical images of clusters of galaxies provides a powerful tool to reconstruct the distribution of the gravitating mass associated to these structures. We use the shear signal extracted by an analysis of deep…

We present a combined cosmic shear analysis of the modeling of line-of-sight distortions on strongly lensed extended arcs and galaxy shape measurements in the COSMOS field. We develop a framework to predict the covariance of strong lensing…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Felix Arjun Kuhn , Claudio Bruderer , Simon Birrer , Adam Amara , Alexandre Réfrégier

The measurement of cosmic shear using weak gravitational lensing is a challenging task that involves a number of complicated procedures. We study in detail the systematic errors in the measurement of weak lensing Minkowski Functionals…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Masato Shirasaki , Naoki Yoshida

Weak gravitational lensing is a powerful probe of the large-scale cosmic matter distribution. Wide-field galaxy surveys allow us to generate the so-called weak lensing maps, but actual observations suffer from noise due to imperfect…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Masato Shirasaki , Naoki Yoshida , Shiro Ikeda

Strong Lensing is a powerful probe of the matter distribution in galaxies and clusters and a relevant tool for cosmography. Analyses of strong gravitational lenses with Deep Learning have become a popular approach due to these astronomical…