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Weak gravitational lensing is one of the most promising cosmological probes to constrain dark matter, dark energy, and the nature of gravity at cosmic scales. Intrinsic alignments (IAs) of galaxies have been recognized as one of the most…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-25 Eske M. Pedersen , Ji Yao , Mustapha Ishak , Pengjie Zhang

We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-20 Tim M. Tugendhat , Bjoern Malte Schaefer

We present cosmological parameter constraints from a tomographic weak gravitational lensing analysis of ~450deg$^2$ of imaging data from the Kilo Degree Survey (KiDS). For a flat $\Lambda$CDM cosmology with a prior on $H_0$ that encompasses…

We present measurements of the cosmic shear correlation in the shapes of galaxies in the Suprime-Cam 2.1 deg^2 R_c-band imaging data. As an estimator of the shear correlation originated from the gravitational lensing, we adopt the aperture…

We measure the alignment of galaxy ellipticities in the local universe over a range of scales using digitized photographic data from the SuperCOSMOS Sky Survey. We find for a magnitude cut of b_J < 20.5, corresponding to a median galaxy…

Astrophysics · Physics 2009-10-31 M. L. Brown , A. N. Taylor , N. C. Hambly , S. Dye

We present a tentative constraint on cosmological parameters $\Omega_m$ and $\sigma_8$ from a joint analysis of galaxy clustering and galaxy-galaxy lensing from DESI Legacy Imaging Surveys Data Release 9 (DR9), covering approximately 10000…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-21 Haojie Xu , Hekun Li , Jun Zhang , Xiaohu Yang , Pengjie Zhang , Min He , Yizhou Gu , Jian Qin , Zhaozhou Li , Antonios Katsianis , Ji Yao , Zhaoyu Wang , Yirong Wang , Liping Fu

Gravitational lensing by large-scale structure induces weak coherent alignments in the shapes of background galaxies. Here we present evidence for the detection of this `cosmic shear' at the 3.4 sigma significance level with the William…

Astrophysics · Physics 2007-05-23 David Bacon , Alexandre Refregier , Richard Ellis

We present a three dimensional cosmic shear analysis of the Hubble Space Telescope COSMOS survey, the largest ever optical imaging program performed in space. We have measured the shapes of galaxies for the tell-tale distortions caused by…

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

In this paper we show how intrinsic alignments can be incorporated consistently in the formalism of 3d weak lensing. We use two different descriptions of the intrinsic galaxy ellipticities, the so-called linear and quadratic model,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Philipp M. Merkel , Bjoern Malte Schaefer

We demonstrate that the intrinsic alignment of galaxies with large-scale tidal fields sources an extra contribution to the recently-detected cross-correlation of galaxy shear and weak lensing of the microwave background. The extra term is…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-22 Alex Hall , Andy Taylor

Gravitational lensing causes background galaxy images to become aligned, and the statistical characteristics of the image alignments can then be used to constrain the power spectrum of mass fluctuations. Analyses of gravitational lensing…

Astrophysics · Physics 2017-08-23 A. F. Heavens

We have analysed 53 square degrees of imaging data from the Red-Sequence Cluster Survey (RCS), and measured the excess correlations in the shapes of galaxies on scales out to ~1.5 degrees. We separate the signal into an ``E''- (lensing) and…

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

The weak lensing signal (cosmic shear) has been shown to be strongly contaminated by the various types of galaxy intrinsic alignment (IA) correlations, which poses a barrier to precision weak lensing measurements. The redshift dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 M. A. Troxel , Mustapha Ishak

Torques acting on galaxies lead to physical alignments, but the resulting ellipticity correlations are difficult to predict. As they constitute a major contaminant for cosmic shear studies, it is important to constrain the intrinsic…

The tangential shear signal receives contributions from physical scales in the galaxy-matter correlation function well below the transverse scale at which it is measured. Since small scales are difficult to model, this non-locality has…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-23 Niall MacCrann , Jonathan Blazek , Bhuvnesh Jain , Elisabeth Krause

Cosmological weak lensing by the large scale structure of the Universe, cosmic shear, is coming of age as a powerful probe of the parameters describing the cosmological model and matter power spectrum. It complements CMB studies, by…

Astrophysics · Physics 2009-11-10 Patrick Simon , Lindsay J. King , Peter Schneider

The galaxy intrinsic alignment causes the galaxy ellipticity-ellipticity power spectrum between two photometric redshifts to decrease faster with respect to the redshift separation $\Delta z^P$, for fixed mean redshift. This offers a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Pengjie Zhang

Measuring the autocorrelation of galaxy shapes, known as the intrinsic-intrinsic (II) correlation, is important for both cosmology and understanding the formation of massive elliptical galaxies. However, such measurements are significantly…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Teppei Okumura

We present a cosmic shear study from the Deep Lens Survey (DLS), a deep BVRz multi-band imaging survey of five 4 sq. degree fields with two National Optical Astronomy Observatory (NOAO) 4-meter telescopes at Kitt Peak and Cerro Tololo. For…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 M. James Jee , J. Anthony Tyson , Michael D. Schneider , David Wittman , Samuel Schmidt , Stefan Hilbert