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Nonlinear cosmological fields like galaxy density and lensing convergence can be approximately related to Gaussian fields via analytic point transforms. The lognormal transform (LN) has been widely used and is a simple example of a function…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-08 Kunhao Zhong , Gary Bernstein , Supranta S. Boruah , Bhuvnesh Jain , Sanjit Kobla

Whilst the underlying assumption of the Friedman-Lema\^itre-Robertson-Walker (FLRW) cosmological model is that matter is homogeneously distributed throughout the universe, gravitational influences over the life of the universe have resulted…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-15 Sonia Akter Ema , Md Rasel Hossen , Krzysztof Bolejko , Geraint F. Lewis

Analytical expressions for covariances of weak lensing statistics related to the aperture mass $\Map$ are derived for realistic survey geometries such as SNAP for a range of smoothing angles and redshift bins. We incorporate the…

Astrophysics · Physics 2009-11-10 Dipak Munshi , Patrick Valageas

We developed a Deep Convolutional Neural Network (CNN), used as a classifier, to estimate photometric redshifts and associated probability distribution functions (PDF) for galaxies in the Main Galaxy Sample of the Sloan Digital Sky Survey…

Instrumentation and Methods for Astrophysics · Physics 2018-12-26 Johanna Pasquet , Emmanuel Bertin , Marie Treyer , Stéphane Arnouts , Dominique Fouchez

We present novel statistical tools to cross-correlate frequency cleaned thermal Sunyaev-Zel'dovich (tSZ) maps and tomographic weak lensing (wl) convergence maps. Moving beyond the lowest order cross-correlation, we introduce a hierarchy of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Dipak Munshi , Shahab Joudaki , Peter Coles , Joseph Smidt , Scott T. Kay

Weak gravitational lensing of background galaxies offers an excellent opportunity to study the intervening distribution of matter. While much attention to date has focused on the two-point function of the cosmic shear, the three-point…

Astrophysics · Physics 2008-11-26 Scott Dodelson , Pengjie Zhang

Current optical imaging surveys for cosmology are covering large areas of sky. To exploit the statistical power of these surveys for weak lensing measurements requires shape measurement methods with subpercent systematic errors. We…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Ricardo Herbonnet , Axel Buddendiek , Konrad Kuijken

An explicit full nulling scheme for cosmic shear observations is presented. It makes possible the construction of shear maps from extended source distributions for which the lens distance distribution is restricted to a definite interval.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Francis Bernardeau , Takahiro Nishimichi , Atsushi Taruya

We introduce the skew-spectrum statistic for weak lensing convergence $\kappa$ maps and test it against state-of-the-art high-resolution all-sky numerical simulations. We perform the analysis as a function of source redshift and smoothing…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 D. Munshi , T. Namikawa , T. D. Kitching , J. D. McEwen , F. R. Bouchet

Weak lensing peak abundance analyses have been applied in different surveys and demonstrated to be a powerful statistics in extracting cosmological information complementary to cosmic shear two-point correlation studies. Future large…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-06 Shuo Yuan , Chuzhong Pan , Xiangkun Liu , Qiao Wang , Zuhui Fan

We present a full-sky derivation of weak lensing observables in the Post-Friedmann (PF) formalism. Weak lensing has the characteristic of mixing small scales and large scales since it is affected by inhomogeneities integrated along the…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Hedda A. Gressel , Camille Bonvin , Marco Bruni , David Bacon

We apply machine learning in the form of a nearest neighbor instance-based algorithm (NN) to generate full photometric redshift probability density functions (PDFs) for objects in the Fifth Data Release of the Sloan Digital Sky Survey (SDSS…

Recently, it has been shown that it is possible to reconstruct the projected mass distribution of a cluster from weak lensing provided that both the geometry of the universe and the probability distribution of galaxy redshifts are known;…

Astrophysics · Physics 2007-05-23 Marco Lombardi , Giuseppe Bertin

Weak gravitational lensing of distant galaxies can probe the total projected mass distribution of foreground gravitational structures on all scales and has been used successfully to map the projected mass distribution of rich intermediate…

Astrophysics · Physics 2007-05-23 L. Van Waerbeke , Y. Mellier

Yes! Upcoming galaxy shear surveys have the potential to significantly improve our understanding of dark energy and neutrino mass if lensing systematics can be sufficiently controlled. The cross-correlations between the weak lensing shear,…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-12 Sudeep Das , Josquin Errard , David Spergel

Weak-lensing peak counts provide a straightforward way to constrain cosmology by linking local maxima of the lensing signal to the mass function. Recent applications to data have already been numerous and fruitful. However, the importance…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-13 Chieh-An Lin , Martin Kilbinger

Weak gravitational lensing provides a sensitive probe of cosmology by measuring the mass distribution and the geometry of the low redshift universe. We show how an all-sky weak lensing tomographic survey can jointly constrain different sets…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-31 Ivan Debono , Anais Rassat , Alexandre Refregier , Adam Amara , Thomas D. Kitching

The COSMOS field has been the subject of a wide range of observations, with a number of studies focusing on reconstructing the 3D dark matter density field. Typically, these studies have focused on one given method or tracer. In this paper,…

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,…

Weak lensing surveys are expected to provide direct measurements of the statistics of the projected dark matter distribution. Most analytical studies of weak lensing statistics have been limited to quasilinear scales as they relied on…

Astrophysics · Physics 2009-10-31 Dipak Munshi , Bhuvnesh Jain