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Gravitational lensing of the CMB is a valuable cosmological signal that correlates to tracers of large-scale structure and acts as a important source of confusion for primordial $B$-mode polarization. State-of-the-art lensing reconstruction…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-05 Julien Carron , Antony Lewis

We develop an algorithm for the reconstruction of the two-dimensional mass distribution of a gravitational lens from the observable distortion of background galaxies. From the measured reduced shear, the lens mapping is obtained, from which…

Astrophysics · Physics 2009-10-31 Tarun Deep Saini , Somak Raychaudhury

Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster,...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power…

Instrumentation and Methods for Astrophysics · Physics 2010-06-08 J. Surdej , C. Delacroix , P. Coleman , M. Dominik , S. Habraken , C. Hanot , H. Le Coroller , D. Mawet , H. Quintana , T. Sadibekova , D. Sluse

(abridged) Aims: RXS J113155.4-123155 (z=0.66) is a quadruply imaged lensed quasar with a resolved Einstein Ring. The goal of this paper is to provide a full characterization of this system, and more particularly accurate astrometry and…

We develop an all-hex meshing strategy for the interstitial space in beds of densely packed spheres that is tailored to turbulent flow simulations based on the spectral element method (SEM). The SEM achieves resolution through elevated…

Computational Engineering, Finance, and Science · Computer Science 2021-06-03 Yu-Hsiang Lan , Paul Fischer , Elia Merzari , Misun Min

We introduce the use of the Fast Multipole Method (FMM) to speed up gravitational lensing ray tracing calculations. The method allows very fast calculation of ray deflections when a large number of deflectors, $N_*$, is involved, while…

Astrophysics of Galaxies · Physics 2022-12-21 J. Jiménez Vicente , E. Mediavilla

In this paper, we propose a new approach -- the Tempered Finite Element Method (TFEM) -- that extends the Finite Element Method (FEM) to classes of meshes that include zero-measure or nearly degenerate elements for which standard FEM…

Numerical Analysis · Mathematics 2024-11-27 Antoine Quiriny , Václav Kučera , Jonathan Lambrechts , Nicolas Moës , Jean-François Remacle

Wavelet functions allow the sparse and efficient representation of a signal at different scales. Recently the application of wavelets to the denoising of maps of cosmic microwave background (CMB) fluctuations has been proposed. The…

Astrophysics · Physics 2009-11-07 Klaus Maisinger , M. P. Hobson , A. N. Lasenby

In this work, we propose a generalized multiscale inversion algorithm for heterogeneous problems that aims at solving an inverse problem on a computational coarse grid. Previous inversion techniques for multiscale problems seek a…

Numerical Analysis · Mathematics 2017-07-27 Eric T. Chung , Yalchin Efendiev , Bangti Jin , Wing Tat Leung , Maria Vasilyeva

Gravity waves (GW) in the early universe generate B-type polarization in the cosmic microwave background (CMB), which can be used as a direct way to measure the energy scale of inflation. Gravitational lensing contaminates the GW signal by…

Astrophysics · Physics 2008-11-26 Uros Seljak , Christopher M. Hirata

Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Adam Rogers , Jason D. Fiege

Strong gravitational lens systems with extended sources are of special interest because they provide additional constraints on the models of the lens systems. To use a gravitational lens system for measuring the Hubble constant, one would…

Astrophysics · Physics 2009-11-11 S. H. Suyu , P. J. Marshall , M. P. Hobson , R. D. Blandford

In Monte Carlo simulations of lattice field theory with a $\theta$ term, one confronts the complex weight problem, or the sign problem. This is circumvented by performing the Fourier transform of the topological charge distribution $P(Q)$.…

High Energy Physics - Lattice · Physics 2017-02-01 Masahiro Imachi , Yasuhiko Shinno , Hiroshi Yoneyama

The directional mean shift (DMS) algorithm is a nonparametric method for pursuing local modes of densities defined by kernel density estimators on the unit hypersphere. In this paper, we show that any DMS iteration can be viewed as a…

Statistics Theory · Mathematics 2021-01-26 Yikun Zhang , Yen-Chi Chen

Realizing high-throughput aberration-corrected Scanning Transmission Electron Microscopy (STEM) exploration of atomic structures requires rapid tuning of multipole probe correctors while compensating for the inevitable drift of the optical…

Machine Learning · Computer Science 2026-01-28 Utkarsh Pratiush , Austin Houston , Richard Liu , Gerd Duscher , Sergei Kalinin

We investigate temperature smearing effects on the electron-boson spectral density function ($I^2\chi(\omega)$) obtained from optical data using a maximum entropy inversion method. We start with two simple model input $I^2\chi(\omega)$,…

Superconductivity · Physics 2016-04-05 Jungseek Hwang

Strong gravitational lensing by galaxies provides us with a unique opportunity to understand the nature of gravity on galactic and extra-galactic scales. In this paper, we propose a new multimessenger approach using data from both…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-08 Tao Yang , Bin Hu , Rong-Gen Cai , Bin Wang

In this manuscript, we provide a comprehensive study of gravitational lensing by dark compact objects predicted by a Modified Gravity (MOG) based on the Scalar-Vector-Tensor action, and the aim is to analyze new insights into the nature of…

General Relativity and Quantum Cosmology · Physics 2025-03-07 Nagina Rehman , Zoe C. S. Chan , Mubasher Jamil , Mustapha Azreg-Aïnou

Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content of galaxies. It also serves as a valuable cosmological probe by allowing us to measure the Hubble constant independently of…

Astrophysics of Galaxies · Physics 2021-03-31 A. Galan , A. Peel , R. Joseph , F. Courbin , J. -L. Starck