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Strong gravitational lensing provides a purely gravitational means to infer properties of dark matter halos and thereby constrain the particle nature of dark matter. Strong lenses sometimes appear as four lensed images of a background…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-20 Daniel Gilman , Simon Birrer , Anna Nierenberg , Maverick S. H. Oh

We propose a novel technique to refine the modelling of galaxy clusters mass distribution using gravitational lensing. The idea is to combine the strengths of both "parametric" and "non-parametric" methods to improve the quality of the fit.…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Eric Jullo , Jean-Paul Kneib

Many high dimensional vector distances tend to a constant. This is typically considered a negative "contrast-loss" phenomenon that hinders clustering and other machine learning techniques. We reinterpret "contrast-loss" as a blessing.…

Computer Vision and Pattern Recognition · Computer Science 2018-04-10 Wen-Yan Lin , Siying Liu , Jian-Huang Lai , Yasuyuki Matsushita

This review forms the Weak Lensing part of the Saas-Fee Advanced Course on Gravitational Lensing. It describes the basicsm applications and results of weak lensing. Contents: (1) Introduction (2) The principles of weak gravitational lensing…

Astrophysics · Physics 2009-11-11 Peter Schneider

We compare the efficiency with which 2D and 3D weak lensing mass mapping techniques are able to detect clusters of galaxies using two state-of-the-art mass reconstruction techniques: MRLens in 2D and GLIMPSE in 3D. We simulate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Adrienne Leonard , Francois Lanusse , Jean-Luc Starck

By considering linear-order departures from general relativity, we compute a novel expression for the weak lensing convergence power spectrum under alternative theories of gravity. This comprises an integral over a 'kernel' of general…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-22 C. Danielle Leonard , Tessa Baker , Pedro G. Ferreira

We study supervised learning problems using clustering constraints to impose structure on either features or samples, seeking to help both prediction and interpretation. The problem of clustering features arises naturally in text…

Machine Learning · Computer Science 2016-09-20 Vincent Roulet , Fajwel Fogel , Alexandre d'Aspremont , Francis Bach

Inverse Problem techniques offer powerful tools which deal naturally with marginal data and asymmetric or strongly smoothing kernels, in cases where parameter-fitting methods may be used only with some caution. Although they are typically…

Astrophysics · Physics 2007-05-23 Norman Gray , Iain J. Coleman

Whilst X-rays and Sunyaev-Zel'dovich observations allow to study the properties of the intra-cluster medium (ICM) of galaxy clusters, their gravitational potential may be constrained using strong gravitational lensing. Although being…

Using stellar dynamics and strong gravitational lensing as complementary probes, Sand et al. (2002, 2003) have recently claimed strong evidence for shallow dark matter density profiles in several lensing clusters, which may conflict with…

Astrophysics · Physics 2007-05-23 Neal Dalal , Charles R. Keeton

We consider an inverse source problem for partially coherent light propagating in the Fresnel regime. The data is the coherence of the field measured away from the source. The reconstruction is based on a minimum residue formulation, which…

A degeneracy in strong lens model is shown analytically. The observed time delays and quasar image positions might {\it not} uniquely determine the concentration and the extent of the lens galaxy halo mass distribution. Simply hardwiring…

Astrophysics · Physics 2009-11-07 HongSheng Zhao , Bo Qin

Selected results on estimating cosmological parameters from simulated weak lensing data with noise are presented. Numerical simulations of ray tracing through N-body simulations have been used to generate shear and convergence maps due to…

Astrophysics · Physics 2007-05-23 Bhuvnesh Jain , Uros Seljak , Simon White

The analysis of optical images of galaxy-galaxy strong gravitational lensing systems can provide important information about the distribution of dark matter at small scales. However, the modeling and statistical analysis of these images is…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-30 Adam Coogan , Konstantin Karchev , Christoph Weniger

Assessing the probability that two or more gravitational waves (GWs) are lensed images of the same source requires an understanding of the image properties, including their relative phase shifts in strong lensing (SL). For non-precessing,…

General Relativity and Quantum Cosmology · Physics 2021-03-31 Jose María Ezquiaga , Daniel E. Holz , Wayne Hu , Macarena Lagos , Robert M. Wald

Lensing by galaxy clusters is a versatile probe of cosmology and extragalactic astrophysics, but the accuracy of some of its predictions is limited by the simplified models adopted to reduce the (otherwise untractable) number of degrees of…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-28 Pietro Bergamini , Adriano Agnello , Gabriel Bartosch Caminha

Disentangled distributed representations of data are desirable for machine learning, since they are more expressive and can generalize from fewer examples. However, for complex data, the distributed representations of multiple objects…

Machine Learning · Computer Science 2016-01-21 Klaus Greff , Rupesh Kumar Srivastava , Jürgen Schmidhuber

We quantify the uncertainty in weak lensing mass estimates of clusters of galaxies, caused by distant (uncorrelated) large scale structure along the line of sight. We find that the effect is fairly small for deep observations (20<R<26) of…

Astrophysics · Physics 2009-11-06 Henk Hoekstra

Gravitational wave (GW) galaxy lens reconstruction is a crucial step for many GW lensing science applications. However, dark siren GW lensing (i.e. lensed GW without observed electromagnetic (EM) counterpart) suffers from similarity…

High Energy Astrophysical Phenomena · Physics 2024-06-17 Jason S. C. Poon , Stefano Rinaldi , Justin Janquart , Harsh Narola , Otto A. Hannuksela

In this work we investigate the weak lensing convergence using an end-to-end nonlinear general relativistic framework. Combining numerical relativity simulations of large-scale structure formation with general relativistic ray-tracing, we…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-27 Hayley J. Macpherson
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