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In this work we introduced a new proposal to study the gravitational lensing theory by spherical lenses, starting from its surface mass density $\Sigma(x)$ written in terms of a decreasing function $f$ of a dimensionless coordinate $x$ on…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-21 Roger Hurtado , Leonardo Castaneda , Juan M. Tejeiro

Subject of this paper are the statistical properties of ellipticity alignments between galaxies evoked by their coupled angular momenta. Starting from physical angular momentum models, we bridge the gap towards ellipticity correlations,…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Federica Capranico , Philipp Merkel , Bjoern Malte Schaefer

Elements of kinematical and dynamical modeling of elliptical galaxies (Es) are presented. In projection, NFW models resemble Sersic models, but with a very narrow range of shapes (m=3+/-1). The total density profile of Es cannot be NFW-like…

Astrophysics · Physics 2009-11-11 G. A. Mamon , E. Lokas , A. Dekel , F. Stoehr , T. J. Cox

Nonnegative matrix factorization (NMF) has been widely used to dimensionality reduction in machine learning. However, the traditional NMF does not properly handle outliers, so that it is sensitive to noise. In order to improve the…

Machine Learning · Computer Science 2022-06-08 Tingting Shen , Junhang Li , Can Tong , Qiang He , Chen Li , Yudong Yao , Yueyang Teng

Galaxy-galaxy lensing is an essential tool for probing dark matter halos and constraining cosmological parameters. While galaxy-galaxy lensing measurements usually rely on shear, weak-lensing magnification contains additional constraining…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jenna K. C. Freudenburg , Eric M. Huff , Christopher M. Hirata

Matter near a gravitational lens galaxy or projected along the line of sight (LOS) can affect strong lensing observables by more than contemporary measurement errors. We simulate lens fields with realistic three-dimensional mass…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 Curtis McCully , Charles R. Keeton , Kenneth C. Wong , Ann I. Zabludoff

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

The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue…

Astrophysics · Physics 2008-11-26 N. W. Evans , H. J. Witt

As we all known, the nonnegative matrix factorization (NMF) is a dimension reduction method that has been widely used in image processing, text compressing and signal processing etc. In this paper, an algorithm for nonnegative matrix…

Numerical Analysis · Mathematics 2013-05-27 Shu-Zhen Lai , Hou-Biao Li , Zu-Tao Zhang

We report the serendipitous discovery of ``Einstein cross'' gravitational lens candidates using the Hubble Space Telescope. We have so far discovered two good examples of such lenses, each in the form of four faint blue images located in a…

Astrophysics · Physics 2009-10-28 Kavan U. Ratnatunga , Eric J. Ostrander , Richard E. Griffiths , Myungshin Im

For 18 well-observed gravitationally lensed QSOs, we compare new non-parametric mass profiles for the lensing galaxies with stellar-population models derived from published HST photometry. The large volume of parameter space searched --…

Astrophysics · Physics 2009-11-10 Ignacio Ferreras , Prasenjit Saha , Liliya L. R. Williams

The lensing signal around galaxy clusters can, in principle, be used to test detailed predictions for their average mass profile from numerical simulations. However, the intrinsic shape of the profiles can be smeared out when a sample that…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Keiichi Umetsu , Benedikt Diemer

We introduce a self-similar mass model for early-type galaxies, and constrain it using the aperture mass-radius relations determined from the geometries of 22 gravitational lenses. The model consists of two components: a concentrated…

Astrophysics · Physics 2008-11-26 D. Rusin , C. S. Kochanek , C. R. Keeton

Future weak lensing surveys potentially hold the highest statistical power for constraining cosmological parameters compared to other cosmological probes. The statistical power of a weak lensing survey is determined by the sky coverage, the…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-05 C. Chang , M. Jarvis , B. Jain , S. M. Kahn , D. Kirkby , A. Connolly , S. Krughoff , E. Peng , J. R. Peterson

In this study, we explore gravitational lensing using more realistic dark matter halo models, moving beyond the limitations of spherical-collapse approximations. Through analytical calculations employing various mass functions, we address…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-13 Ali Tizfahm , Saeed Fakhry , Javad T. Firouzjaee , Antonino Del Popolo

We present two new tools for studying and modelling metal absorption lines in the circumgalactic medium. The first tool, dubbed ``NMF Profile Maker'' (NMF$-$PM), uses a non-negative matrix factorization (NMF) method and provides a robust…

We demonstrate an efficient method to compute the strong-gravitational-lensing deflection angle and magnification for any elliptical surface-density profile. This method solves a numerical hurdle in lens modelling that has lacked a general…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-10 Anowar J. Shajib

We introduce a new adaptive and fully Bayesian grid-based method to model strong gravitational lenses with extended images. The primary goal of this method is to quantify the level of luminous and dark-mass substructure in massive galaxies,…

Astrophysics · Physics 2009-11-13 S. Vegetti , L. V. E. Koopmans

Non-negative Matrix Factorization (NMF) is one of the most popular techniques for data representation and clustering, and has been widely used in machine learning and data analysis. NMF concentrates the features of each sample into a…

Image and Video Processing · Electrical Eng. & Systems 2021-03-26 Mulin Chen , Maoguo Gong , Xuelong Li

In this series of papers we develop a formalism for constraining mass profiles in strong gravitational lenses with extended images, using fluxes in addition to positional information. We start in this paper with a circular power-law profile…

Astrophysics of Galaxies · Physics 2019-06-26 Conor M. O'Riordan , Stephen J. Warren , Daniel J. Mortlock