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This paper presents a new method for the reconstruction of weak lensing mass maps. It uses the multiscale entropy concept, which is based on wavelets, and the False Discovery Rate which allows us to derive robust detection levels in wavelet…

Astrophysics · Physics 2009-11-10 Jean-Luc Starck , Sandrine Pires , Alexandre Refregier

Accurate weak-lensing analysis requires not only accurate measurement of galaxy shapes but also precise and unbiased measurement of galaxy redshifts. The photometric redshift technique appears as the only possibility to determine the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 S. Jouvel , J-P. Kneib , G. Bernstein , O. Ilbert , P. Jelinsky , B. Milliard , A. Ealet , C. Schimd , T. Dahlen , S. Arnouts

Highly precise weak lensing shear measurement is required for statistical weak gravitational lensing analysis such as cosmic shear measurement to achieve severe constraint on the cosmological parameters. For this purpose, the accurate shape…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-18 Yuki Okura , Toshifumi Futamase

Weak lensing measurements are starting to provide statistical maps of the distribution of matter in the universe that are increasingly precise and complementary to cosmic microwave background maps. The probability distribution (PDF)…

Astrophysics · Physics 2009-11-10 Tong-Jie Zhang , Ue-Li Pen

Weak lensing surveys have become a powerful tool for mapping mass distributions and constraining the expansion history of our Universe, but continuum surveys must average over a large number of galaxies to average down the ellipticity noise…

Astrophysics · Physics 2009-11-11 Miguel F. Morales

We present an end-to-end methodology to measure the effects of weak lensing on individual galaxy-galaxy systems exploiting their kinematic information. Using this methodology, we have measured a shear signal from the velocity fields of 18…

Astrophysics of Galaxies · Physics 2020-09-22 Pol Gurri , Edward N. Taylor , Christopher J. Fluke

Image distortion due to weak gravitational lensing is examined using a non-perturbative method of integrating the geodesic deviation and optical scalar equations along the null geodesics connecting the observer to a distant source. The…

General Relativity and Quantum Cosmology · Physics 2011-09-28 Thomas P. Kling , Louis Bianchini

Intrinsic alignments of galaxies can mimic to an extent the effects of shear caused by weak gravitational lensing. Previous studies have shown that for shallow surveys with median redshifts z_m = 0.1, the intrinsic alignment dominates the…

Astrophysics · Physics 2009-11-07 Catherine Heymans , Alan Heavens

We study the reliability of dark-matter halo detections with three different linear filters applied to weak-lensing data. We use ray-tracing in the multiple lens-plane approximation through a large cosmological simulation to construct…

We propose a novel bias-free method for reconstructing the power spectrum of the weak lensing deflection field from cosmic microwave background (CMB) observations. The proposed method is in contrast to the standard method of CMB lensing…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-30 Blake D. Sherwin , Sudeep Das

We present the results of weak gravitational lensing statistics in four different cosmological $N$-body simulations. The data has been generated using an algorithm for the three-dimensional shear, which makes use of a variable softening…

Astrophysics · Physics 2009-10-31 Andrew J. Barber , Peter A. Thomas , H. M. P. Couchman , C. J. Fluke

Kaiser & Squires have proposed a technique for mapping the dark matter in galaxy clusters using the coherent weak distortion of background galaxy images caused by gravitational lensing. We investigate the effectiveness of this technique…

Astrophysics · Physics 2015-06-24 Gillian Wilson , Shaun Cole , Carlos S. Frenk

Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are…

Astrophysics · Physics 2009-09-29 D. Munshi , P. Valageas , L. Van Waerbeke , A. Heavens

The standard theory of weak gravitational lensing relies on the approximation that light beams are infinitesimal. Our recent work showed that the finite size of sources, and the associated light beams, can cause nonperturbative corrections…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-29 Pierre Fleury , Julien Larena , Jean-Philippe Uzan

Weak gravitational lensing provides a unique method to directly map the dark matter in the universe and measure cosmological parameters. Current weak lensing surveys are limited by the atmospheric seeing from the ground and by the small…

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging…

Astrophysics · Physics 2009-11-13 C. Marois , D. Lafreniere , B. Macintosh , R. Doyon

So far, estimators of galaxy shape distortions are only carefully studied perturbatively in the case of small shear signals, mainly for weak lensing science. However, in the neighborhood of massive foreground clusters, a large number of…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-08 Jiarui Sun , Jun Zhang , Li Cui , Alessandro Sonnenfeld , Xin Wang

Weak lensing is one of the best available diagnostic tools to measure the total density profiles of distant clusters of galaxies. Unfortunately, it suffers from the well-known mass-sheet degeneracy, so that weak lensing analyses cannot lead…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Alessandro Sonnenfeld , Giuseppe Bertin , Marco Lombardi

Due to observational constraints, dark matter determinations in nearby clusters based on weak lensing are still extremely rare, in spite of their importance for the determination of cluster properties independent of other methods. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Raphael Gavazzi , Christophe Adami , Florence Durret , Jean-Charles Cuillandre , Olivier Ilbert , Alain Mazure , Roser Pello , Melville P. Ulmer

We present a new method to determine the total mass-to-neutral gas ratio in Lyman-limits systems. The method exploits the relation between the neutral hydrogen column density and the magnification of background sources due to the weak…

Astrophysics · Physics 2009-11-06 Ariyeh Maller , Tsafrir Kolatt , Matthias Bartelmann , George R. Blumenthal