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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

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 next generation of weak lensing probes can place strong constraints on cosmological parameters by measuring the mass distribution and geometry of the low redshift universe. We show that a future all-sky tomographic cosmic shear survey…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Ivan Debono

We derive expressions, in terms of "polar shapelets", for the image distortion operations associated with weak gravitational lensing. Shear causes galaxy shapes to become elongated, and is sensitive to the second derivative of the projected…

Astrophysics · Physics 2008-11-26 Richard Massey , Barnaby Rowe , Alexandre Refregier , David J. Bacon , Joel Berge

Weak lensing is emerging as a powerful observational tool to constrain cosmological models, but is at present limited by an incomplete understanding of many sources of systematic error. Many of these errors are multiplicative and depend on…

Weak lensing by large scale structure or 'cosmic shear' is a potentially powerful cosmological probe to shed new light on Dark Matter, Dark Energy and Modified Gravity. It is based on the weak distortions induced by large-scale structures…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-11 Alexandre Refregier , Adam Amara

We present cosmological constraints from 2D weak gravitational lensing by the large-scale structure in the Canada-France Hawaii Telescope Lensing Survey (CFHTLenS) which spans 154 square degrees in five optical bands. Using accurate…

Weak lensing by large-scale structure allows a direct measure of the dark matter distribution. We have used parallel images taken with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope to measure weak lensing, or…

Convolutional Neural Networks (CNN) have recently been demonstrated on synthetic data to improve upon the precision of cosmological inference. In particular they have the potential to yield more precise cosmological constraints from weak…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-17 Janis Fluri , Tomasz Kacprzak , Aurelien Lucchi , Alexandre Refregier , Adam Amara , Thomas Hofmann , Aurel Schneider

We perform a combined analysis of cosmic shear tomography, galaxy-galaxy lensing tomography, and redshift-space multipole power spectra (monopole and quadrupole) using 450 deg$^2$ of imaging data by the Kilo Degree Survey (KiDS) overlapping…

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

We propose a new ray-tracing algorithm to measure the weak lensing shear and convergence fields directly from N-body simulations. We calculate the deflection of the light rays lensed by the 3-D mass density field or gravitational potential…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Baojiu Li , Lindsay J. King , Gong-Bo Zhao , HongSheng Zhao

We apply two Bayesian hierarchical inference schemes to infer shear power spectra, shear maps and cosmological parameters from the CFHTLenS weak lensing survey - the first application of this method to data. In the first approach, we sample…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-10 Justin Alsing , Alan F. Heavens , Andrew H. Jaffe

A cross-correlation technique of lensing tomography is presented to measure the evolution of dark energy in the universe. The variation of the weak lensing shear with redshift around massive foreground objects like bright galaxies and…

Astrophysics · Physics 2008-11-26 Bhuvnesh Jain , Andy Taylor

Dedicated 'Stage IV' observatories will soon observe the entire extragalactic sky, to measure the 'cosmic shear' distortion of galaxy shapes by weak gravitational lensing. To measure the apparent shapes of those galaxies, we present an…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Xiangchong Li , Yin Li , Richard Massey

Weak lensing provides a direct measure of the distribution of mass in the universe, and is therefore a uniquely powerful probe of dark matter. Weak lensing can also be used to measure the twin phenomenon of dark energy, via its effect upon…

Astrophysics · Physics 2007-05-23 Richard Massey , Alexandre Refregier , Jason Rhodes

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. Nowadays, attention has shifted from clusters of galaxies to the statistical properties…

Astrophysics · Physics 2009-11-07 Henk Hoekstra , Howard Yee , Mike Gladders

Weak gravitational lensing has become a common tool to constrain the cosmological model. The majority of the methods to derive constraints on cosmological parameters use second-order statistics of the cosmic shear. Despite their success,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Sandrine Pires , Adrienne Leonard , Jean-Luc Starck

With a primary goal of conducting precision weak lensing measurements from space, the COSMOS survey has imaged the largest contiguous area observed by the Hubble Space Telescope (HST) to date using the Advanced Camera for Surveys (ACS).…

The nature of the dark matter remains a mystery. The possibility of an unstable dark matter particle decaying to invisible daughter particles has been explored many times in the past few decades. Meanwhile, weak gravitational lensing shear…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-24 Mei-Yu Wang , Andrew R. Zentner