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We show with analytic models that the assumption of uncorrelated intrinsic ellipticities of target sources that is usually made in searches for weak gravitational lensing due to large-scale mass inhomogeneities (``field lensing'') is…

Astrophysics · Physics 2009-12-15 Paolo Catelan , Marc Kamionkowski , Roger D. Blandford

We investigate the impact of the observed correlation between a galaxies shape and its surrounding density field on the measurement of third order weak lensing shear statistics. Using numerical simulations, we estimate the systematic error…

Intrinsic alignments are believed to be a major source of systematics for future generation of weak gravitational lensing surveys like Euclid or LSST. Direct measurements of the alignment of the projected light distribution of galaxies in…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Sandrine Codis , Yohan Dubois , Christophe Pichon , Julien Devriendt , Adrianne Slyz

The weak gravitational lensing effect, small coherent distortions of galaxy images by means of a gravitational tidal field, can be used to study the relation between the matter and galaxy distribution. In this context, weak lensing has so…

Astrophysics · Physics 2014-11-18 P. Simon , P. Watts , P. Schneider , H. Hoekstra , M. D. Gladders , H. K. C. Yee , B. C. Hsieh , H. Lin

Subject of this paper are intrinsic ellipticity correlations between galaxies, their statistical properties, their observability with future surveys and their interference with weak gravitational lensing measurements. Using an angular…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-25 Bjoern Malte Schaefer , Philipp M. Merkel

The angular correlation function \wth of faint galaxies is affected both by nonlinear gravitational evolution and by magnification bias due to gravitational lensing. We compute the resulting \wth for different cosmological models and show…

Astrophysics · Physics 2020-11-25 R. Moessner , B. Jain , J. V. Villumsen

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

Galaxy intrinsic alignment can be a severe source of error in weak-lensing studies. The problem has been widely studied by numerical simulations and with heuristic models, but without a clear theoretical justification of its origin and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-11 Giovanni Camelio , Marco Lombardi

Intrinsic galaxy alignments constitute the major astrophysical systematic of forthcoming weak gravitational lensing surveys but also yield unique insights into galaxy formation and evolution. We build analytic models for the distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-07 B. Joachimi , E. Semboloni , S. Hilbert , P. E. Bett , J. Hartlap , H. Hoekstra , P. Schneider

Weak lensing by large scale structure induces correlated ellipticities in the images of distant galaxies. The two-point correlation is determined by the matter power spectrum along the line of sight. We use the fully nonlinear evolution of…

Astrophysics · Physics 2009-10-28 Bhuvnesh Jain , Uros Seljak

Observational evidence shows that gravitational lensing induces an angular correlation between the distribution of galaxies and much more distant QSOs. We use weak gravitational lensing theory to calculate this angular correlation, updating…

Alignments of spiral galaxies were thought to result from tidal torquing, where tidal field of the cosmic large-scale structure exert torquing moments onto dark matter haloes, determining their angular momentum and ultimately the…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-24 Basundhara Ghosh , Kai Nussbaumer , Eileen Sophie Giesel , Björn Malte Schäfer

The distortion field defined by the ellipticities of galaxy shapes projected on the sky can be uniquely decomposed into a gradient and a curl component. If the observed ellipticities are induced by weak gravitational lensing, then the…

Astrophysics · Physics 2011-09-30 Robert G. Crittenden , Priyamvada Natarajan , Ue-Li Pen , Tom Theuns

Vector perturbations sourced by topological defects can generate rotations in the lensing of background galaxies. This is a potential smoking gun for the existence of defects since rotation generates a curl-like component in the weak…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 Daniel B. Thomas , Carlo R. Contaldi , Joao Magueijo

Cosmological weak lensing gives rise to correlations in the ellipticities of faint galaxies. This cosmic shear signal depends upon the matter power spectrum, thus providing a means to constrain cosmological parameters. It has recently been…

Astrophysics · Physics 2009-11-07 Lindsay King , Peter Schneider

Weak lensing by large-scale mass inhomogeneities in the Universe induces correlations in the observed ellipticities of distant sources. We first review the harmonic analysis and statistics required of these correlations and discuss…

Astrophysics · Physics 2009-10-30 Marc Kamionkowski , Arif Babul , Catherine M. Cress , Alexandre Refregier

The measurement of the integrated optical polarization of weakly gravitationally lensed galaxies can provide considerable constraints on lens models. The method outlined depends on fact that the orientation of the direction of optical…

Astrophysics · Physics 2009-10-30 Edouard Audit , John F. L. Simmons

Galaxy shapes are not randomly oriented, rather they are statistically aligned in a way that can depend on formation environment, history and galaxy type. Studying the alignment of galaxies can therefore deliver important information about…

The wealth of incoming and future cosmological observations will allow us to map out the structure and evolution of the observable universe to an unprecedented level of precision. Among these observations is the weak gravitational lensing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 M. A. Troxel , Mustapha Ishak

The measurement of shape parameters of sources in astronomical images is usually performed by assuming that the underlying noise is uncorrelated. Spatial noise correlation is however present in practice due to various observational effects…

Astrophysics · Physics 2007-05-23 A. Refregier , S. T. Brown