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We present a new shear calibration method based on machine learning. The method estimates the individual shear responses of the objects from the combination of several measured properties on the images using supervised learning. The…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-25 Arnau Pujol , Jerome Bobin , Florent Sureau , Axel Guinot , Martin Kilbinger

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

The existing large scale weak lensing surveys typically reserve the best seeing conditions for a certain optical band to minimize shape measurement errors and maximize the number of usable background galaxies. This is because most popular…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-02 Cong Liu , Jun Zhang , Hekun Li , Pedro Alonso Vaquero , Wenting Wang

A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ($\simeq$15 seconds) proposed, the…

Metacalibration is a state-of-the-art technique for measuring weak gravitational lensing shear from well-sampled galaxy images. We investigate the accuracy of shear measured with metacalibration from fitting elliptical Gaussians to…

Instrumentation and Methods for Astrophysics · Physics 2021-03-03 Arun Kannawadi , Erik Rosenberg , Henk Hoekstra

The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is a Guaranteed Time program carried out with the ESO/VST telescope to provide deep optical imaging over two 4 deg$^2$ patches of the sky centred on the CDFS and ES1…

Studies of weak gravitational lensing by large-scale structures require the measurement of the distortions introduced to the shapes of distant galaxies at the few percent level by anisotropic light deflection along the line of sight. To…

Astrophysics · Physics 2009-11-07 Andrew W. Blain

Statistical weak lensing by large-scale structure -- cosmic shear -- is a promising cosmological tool, which has motivated the design of several large upcoming surveys. Here, we present a measurement of cosmic shear using coadded Sloan…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-15 Eric M. Huff , Tim Eifler , Christopher M. Hirata , Rachel Mandelbaum , David Schlegel , Uros Seljak

We study the covariance properties of real space correlation function estimators -- primarily galaxy-shear correlations, or galaxy-galaxy lensing -- using SDSS data for both shear catalogs and lenses (specifically the BOSS LOWZ sample).…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-30 Sukhdeep Singh , Rachel Mandelbaum , Uroš Seljak , Anže Slosar , Jose Vazquez Gonzalez

Weak gravitational lensing shear could be measured far more precisely if information about unlensed attributes of source galaxies were available. Disk galaxy velocity fields supply such information, at least in principle, with idealized…

Instrumentation and Methods for Astrophysics · Physics 2023-03-15 Jean Donet , David Wittman

We explore the cosmological constraints from cosmic shear using a new way of modelling the non-linear matter correlation functions. The new formalism extends the method of Angulo & White (2010), which manipulates outputs of $N$-body…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Raul E. Angulo , Stefan Hilbert

We develop a new method to estimate gravitational shear by adopting an elliptical weight function to measure background galaxy images. In doing so, we introduce a new concept of "zero plane" which is an imaginal source plane where shapes of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Yuki Okura , Toshifumi Futamase

Weak gravitational lensing is a powerful probe for constraining cosmological parameters, but its success relies on accurate shear measurements. In this paper, we use image simulations to investigate how a joint analysis of high-resolution…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-22 Shiyang Zhang , Shun-Sheng Li , Henk Hoekstra

Kinematic weak lensing describes the distortion of a galaxy's projected velocity field due to lensing shear, an effect recently reported for the first time by Gurri et al. based on a sample of 18 galaxies at $z \sim 0.1$. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Brian DiGiorgio , Kevin Bundy , Kyle B. Westfall , Alexie Leauthaud , David Stark

Weak gravitational lensing of distant galaxies provides a powerful probe of dark energy. The aim of this study is to investigate the application of convolutional neural networks (CNNs) to precision shear estimation. In particular, using a…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-06 Lisa Voigt

We investigate the sensitivity to the effects of lensing magnification on large-scale structure analyses combining photometric cosmic shear and galaxy clustering data (i.e. the now commonly called "3$\times$2-point" analysis). Using a…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Leander Thiele , Christopher A. J. Duncan , David Alonso

The decomposition of the cosmic shear field into E- and B-mode is an important diagnostic in weak gravitational lensing. However, commonly used techniques to perform this separation suffer from mode-mixing on very small or very large…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Liping Fu , Martin Kilbinger

With the recent detection of cosmic shear, the most challenging effect of weak gravitational lensing has been observed. The main difficulties for this detection were the need for a large amount of high quality data and the control of…

The weak gravitational lensing distortion of distant galaxy images (defined as sources) probes the projected large-scale matter distribution in the Universe. To improve quality in the 3D mass mapping using 3D-lensing, we combine the lensing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Patrick Simon

The ratio of the average tangential shear signal of different weak lensing source populations around the same lens galaxies, also known as a shear ratio, provides an important test of lensing systematics and a potential source of…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-01 Ni Emas , Chris Blake , Rossana Ruggeri , Anna Porredon
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