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Many distant objects can only be detected, or become more scientifically valuable, if they have been highly magnified by strong gravitational lensing. We use EAGLE and BAHAMAS, two recent cosmological hydrodynamical simulations, to predict…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Andrew Robertson , Graham P. Smith , Richard Massey , Vincent Eke , Mathilde Jauzac , Matteo Bianconi , Dan Ryczanowski

We investigate the effects of weak gravitational lensing in the standard Cold Dark Matter cosmology, using an algorithm which evaluates the shear in three dimensions. The algorithm has the advantage of variable softening for the particles,…

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

The total mass of clusters of galaxies is a key parameter to study massive halos. It relates to numerous gravitational and baryonic processes at play in the framework of large scale structure formation, thus rendering its determination…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 G. Foëx , G. Soucail , E. Pointecouteau , M. Arnaud , M. Limousin , G. W. Pratt

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

Weak gravitational lensing has been used extensively in the past decade to constrain the masses of galaxy clusters, and is the most promising observational technique for providing the mass calibration necessary for precision cosmology with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Rachel Mandelbaum , Uros Seljak , Tobias Baldauf , Robert E. Smith

This chapter provides a comprehensive overview of weak gravitational lensing and its current applications in cosmology. We begin by introducing the fundamental concepts of gravitational lensing and derive the key equations for the…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-06 J. Prat , D. Bacon

We develop an algorithm for the reconstruction of the two-dimensional mass distribution of a gravitational lens from the observable distortion of background galaxies. From the measured reduced shear, the lens mapping is obtained, from which…

Astrophysics · Physics 2009-10-31 Tarun Deep Saini , Somak Raychaudhury

Future weak lensing surveys will directly probe the clustering of dark matter, in addition to providing a test for various cosmological models. Recent studies have provided us with the tools which can be used to construct the complete…

Astrophysics · Physics 2009-11-07 Dipak Munshi , Yun Wang

We study the biasing relation between dark-matter halos or galaxies and the underlying mass distribution, using cosmological $N$-body simulations in which galaxies are modelled via semi-analytic recipes. The nonlinear, stochastic biasing is…

Astrophysics · Physics 2009-09-25 R. S. Somerville , G. Lemson , Y. Sigad , A. Dekel , G. Kauffmann , S. D. M. White

It is common practice in cosmology to model large-scale structure observables as lognormal random fields, and this approach has been successfully applied in the past to the matter density and weak lensing convergence fields separately. We…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-18 Henrique S. Xavier , Filipe B. Abdalla , Benjamin Joachimi

We present an investigation into a hitherto unexplored systematic that affects the accuracy of galaxy cluster mass estimates with weak gravitational lensing. Specifically, we study the covariance between the weak lensing signal,…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-10 Zhuowen Zhang , Arya Farahi , Daisuke Nagai , Erwin T. Lau , Joshua Frieman , Marina Ricci , Anja von der Linden , Hao-yi Wu

We introduce a novel approach to reconstruct dark matter mass maps from weak gravitational lensing measurements. The cornerstone of the proposed method lies in a new modelling of the matter density field in the Universe as a mixture of two…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-26 J. -L. Starck , K. E. Themelis , N. Jeffrey , A. Peel , F. Lanusse

Weak gravitational lensing, the deflection of light by mass, is one of the best tools to constrain the growth of cosmic structure with time and reveal the nature of dark energy. I discuss the sources of systematic uncertainty in weak…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Rachel Mandelbaum

We propose a physical model for nonlinear stochastic biasing of one-point statistics resulting from the formation epoch distribution of dark halos. In contrast to previous works on the basis of extensive numerical simulations, our model…

Astrophysics · Physics 2009-10-16 Atsushi Taruya , Yasushi Suto

The mathematical theory of gravitational lensing has revealed many generic and global properties. Beginning with multiple imaging, we review Morse-theoretic image counting formulas and lower bound results, and complex-algebraic upper bounds…

Astrophysics of Galaxies · Physics 2014-11-20 A. O. Petters , M. C. Werner

Analysing the weak lensing distortions of the images of faint background galaxies provides a means to constrain the average mass distribution of cluster galaxies and potentially to test the extent of their dark matter haloes as a function…

Astrophysics · Physics 2009-10-30 Bernhard Geiger , Peter Schneider

Significant adjustments to the values of the cosmological parameters estimated from high-redshift Type Ia Supernov\ae data are reported, almost an order of magnitude greater than previously found. They arise from the effects of weak…

Astrophysics · Physics 2009-10-31 Andrew J. Barber

Peak counts have been shown to be an excellent tool to extract the non-Gaussian part of the weak lensing signal. Recently, we developped a fast stochastic forward model to predict weak-lensing peak counts. Our model is able to reconstruct…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-16 Chieh-An Lin , Martin Kilbinger

We use the semi-analytical approach to analyze gravitational lensing of quasars by dark halos in various cold dark matter (CDM) cosmologies, in order to determine the sensitivity of the prediction probabilities of images separations to the…

Astrophysics · Physics 2009-10-31 Li-Xin Li , Jeremiah P. Ostriker

Distribution of galaxies may be a biased tracer of the dark matter distribution and the relation between the galaxies and the total mass may be stochastic, non-linear and time-dependent. Since many observations of galaxy clustering will be…

Astrophysics · Physics 2009-10-31 Atsushi Taruya