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Using overlapping fields with space-based Hubble Space Telescope (HST) and ground-based Subaru Telescope imaging we identify a population of blended galaxies that are blended to such a large degree that they are detected as single objects…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 William A. Dawson , Michael D. Schneider , J. Anthony Tyson , M. James Jee

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

In weak gravitational lensing, the image distortion caused by shear measures the projected tidal gravitational field of the deflecting mass distribution. To lowest order, the shear is proportional to the mean image ellipticity. If the image…

Astrophysics · Physics 2009-11-13 Peter Schneider , Xinzhong Er

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

We examine the cosmological constraining power of future large-scale weak lensing surveys on the model of \emph{Euclid}, with particular reference to primordial non-Gaussianity. Our analysis considers several different estimators of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 C. Fedeli , M. Bartelmann , L. Moscardini

In this work we investigate the environmental dependence of the intrinsic ellipticity correlations in cosmic shear surveys. We use the quadratic and linear alignment model to describe the contributions by spiral and elliptical galaxies,…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-05 Robert Reischke , Björn Malte Schäfer

We have developed a new three-dimensional algorithm, based on the standard P$^3$M method, for computing deflections due to weak gravitational lensing. We compare the results of this method with those of the two-dimensional planar approach,…

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

Combining redshift and galaxy shape information offers new exciting ways of exploiting the gravitational lensing effect for studying the large scales of the cosmos. One application is the three-dimensional reconstruction of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Patrick Simon , Andy Taylor , Jan Hartlap

The statistical properties of the ellipticities of galaxy images depend on how galaxies form and evolve, and therefore constrain models of galaxy morphology, which are key to the removal of the intrinsic alignment contamination of…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-28 B. Joachimi , E. Semboloni , P. E. Bett , J. Hartlap , S. Hilbert , H. Hoekstra , P. Schneider , T. Schrabback

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

Weak gravitational lensing (WL) peak statistics capture cosmic non-linear structures and can provide additional cosmological information complementary to cosmic shear two-point correlation analyses. They have been applied to different WL…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Tianyu Zhang , Xiangkun Liu , Ziwei Li , Chengliang Wei , Guoliang Li , Yu Luo , Xi Kang , Zuhui Fan

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

Weak gravitational lensing has become a widely used effect to characterise the dark-matter distribution on large scales in the Universe by measuring galaxy ellipticities and their statistical correlations. We present the first weak…

Sample selection is a necessary preparation for weak lensing measurement. It is well-known that selection itself may introduce bias in the measured shear signal. Using image simulation and the Fourier_Quad shear measurement pipeline, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-04 Hekun Li , Jun Zhang , Dezi Liu , Wentao Luo , Jiajun Zhang , Fuyu Dong , Zhi Shen , Haoran Wang

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

Weak gravitational lensing seeks to determine shear by measuring induced quadrupole (elliptical) shapes in background galaxy images. Small impact parameter (a few kpc) gravitational lensing by foreground core masses between 2 10^{9} and 2…

Astrophysics · Physics 2014-10-13 John Irwin , Marina Shmakova

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

Weak lensing statistics is typically measured as weighted sum of shear estimators or their products (shear-shear correlation). The weighting schemes are designed in the hope of minimizing the statistical error without introducing systematic…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-24 Jun Zhang , Pengjie Zhang , Wentao Luo

We present new measurements of dark matter distributions in 25 X-ray luminous clusters by making a full use of the two-dimensional (2D) weak lensing signals obtained from high-quality Subaru/Suprime-Cam imaging data. Our approach to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Masamune Oguri , Masahiro Takada , Nobuhiro Okabe , Graham P. Smith

We present and describe im3shape, a new publicly available galaxy shape measurement code for weak gravitational lensing shear. im3shape performs a maximum likelihood fit of a bulge-plus-disc galaxy model to noisy images, incorporating an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Joe Zuntz , Tomasz Kacprzak , Lisa Voigt , Michael Hirsch , Barnaby Rowe , Sarah Bridle