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Weak gravitational lensing has several important effects on the cosmic microwave background (CMB): it changes the CMB power spectra, induces non-Gaussianities, and generates a B-mode polarization signal that is an important source of…

Astrophysics · Physics 2007-05-23 Antony Lewis , Anthony Challinor

We propose to use a simple observable, the fractional area of "hot spots" in weak lensing mass maps which are detected with high significance, to determine background cosmological parameters. Because these high-shear regions are directly…

Astrophysics · Physics 2008-09-24 Sheng Wang , Zoltan Haiman , Morgan May , John Kehayias

Weak gravitational lensing by the intervening large-scale structure (LSS) of the Universe is the leading non-linear effect on the anisotropies of the cosmic microwave background (CMB). The integrated line-of-sight mass that causes the…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Alba Kalaja , Giorgio Orlando , Aleksandr Bowkis , Anthony Challinor , P. Daniel Meerburg , Toshiya Namikawa

We compute the angular power spectrum of the $B$-modes of the weak-lensing shear in a spatially anisotropic spacetime. We find that there must also exist off-diagonal correlations between the $E$-modes, $B$-modes, and convergence that allow…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-13 Thiago S. Pereira , Cyril Pitrou , Jean-Philippe Uzan

We investigate the origin of $\Lambda$CDM parameter constraints in weak lensing, with a focus on the Hubble constant. We explain why current cosmic shear data are sensitive to the parameter combination $S_8 \propto \sigma_8 \Omega_m^{0.5}$,…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 Alex Hall

We consider the weak lensing effect induced by linear cosmological perturbations on the cosmic microwave background (CMB) polarization anisotropies. We find that the amplitude of the lensing peak in the BB mode power spectrum is a faithful…

Astrophysics · Physics 2009-11-13 Viviana Acquaviva , Carlo Baccigalupi

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 lensing is a potentially robust and model-independent cosmological probe, but its accuracy is dependent on knowledge of the redshift distribution of the source galaxies used. The most robust way to determine the redshift distribution…

Astrophysics · Physics 2009-11-10 Mustapha Ishak , Christopher M. Hirata

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 tomographic weak lensing surveys, the presence of nulling properties reveals symmetries inherent in the data, which rely solely on the geometrical properties of the Universe. Ensuring its validity thus provides us with constraints on the…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-05 David Touzeau , Francis Bernardeau , Karim Benabed , Sandrine Codis

The second-order vector mode is inevitably induced from the coupling of first-order scalar modes in cosmological perturbation theory and might hinder a possible detection of primordial gravitational waves from inflation through 21cm lensing…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-22 Shohei Saga

Here we present a number of improvements to weak lensing 3D power spectrum analysis, 3D cosmic shear, that uses the shape and redshift information of every galaxy to constrain cosmological parameters. We show how photometric redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 T. D. Kitching , A. F. Heavens , L. Miller

We estimate the impact of weak lensing by strongly nonlinear cosmological structures on the cosmic microwave background. Accurate calculation of large $\ell$ multipoles requires N-body simulations and ray-tracing schemes with both high…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 M. J. Fullana , J. V. Arnau , R. J. Thacker , H. M. P. Couchman , D. Sáez

Modelling of the weak lensing of the CMB will be crucial to obtain correct cosmological parameter constraints from forthcoming precision CMB anisotropy observations. The lensing affects the power spectrum as well as inducing…

Astrophysics · Physics 2010-11-17 Antony Lewis

CMB anisotropies are modified by the weak lensing effect of intervening large scale structures on the photon path from the last scattering surface to the observer. This has to be accounted for when observational data of sensitive…

Astrophysics · Physics 2010-10-27 Jonathan Rocher , Karim Benabed , Francois Bouchet

Flexion is the weak lensing effect responsible for the weakly skewed and arc-like appearance of lensed galaxies. The flexion signal-to-noise ratio can be an order of magnitude larger than that of shear. For the first time, we show how this…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-21 Stefano Camera , Antonaldo Diaferio

We present a tomographic cosmological weak lensing analysis of the HST COSMOS Survey. Applying our lensing-optimized data reduction, principal component interpolation for the ACS PSF, and improved modelling of charge-transfer inefficiency,…

The Cosmic Microwave Background (CMB) radiation lensing is a promising tool to study the physics of early universe. In this work we probe the imprints of deviations from isotropy and scale invariance of primordial curvature perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-01 Farbod Hassani , Shant Baghram , Hassan Firouzjahi

This article details the computation of the two-point correlators of the convergence, $E$- and $B$-modes of the cosmic shear induced by the weak-lensing by large scale structure assuming that the background spacetime is spatially…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-13 Cyril Pitrou , Thiago S. Pereira , Jean-Philippe Uzan

We report a detection of the coherent distortion of faint galaxies arising from gravitational lensing by foreground structures. This ``cosmic shear'' is potentially the most direct measure of the mass power spectrum, as it is unaffected by…

Astrophysics · Physics 2011-05-05 David Bacon , Alexandre Refregier , Richard Ellis