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We present new Hubble Space Telescope images of the gravitational lens PKS 1830-211, which allow us to characterize the lens galaxy and update the determination of the Hubble constant from this system. The I-band image shows that the lens…

Clusters of galaxies have a huge mass which can act as gravitational lenses. Galaxies behind clusters can be distorted to form arcs in images by the lenses. Herein a search was done for giant lensed arcs by galaxy clusters using the SDSS…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-21 S. M. Liang , Z. L. Wen , J. L. Han , Y. Y. Jiang

We study the correlation between the locations of galaxy-galaxy strong lensing candidates and tracers of large-scale structure from both weak lensing or X-ray emission. The COSMOS survey is a unique data set, combining deep, high resolution…

Dark matter caustics have specific density profiles and, therefore, precisely calculable gravitational lensing properties. We present a formalism which simplifies the relevant calculations, and apply it to four specific cases. In the first…

Astrophysics · Physics 2009-11-07 C. Charmousis , V. Onemli , Z. Qiu , P. Sikivie

In this work the space-time geometry of the halo region in spiral galaxies is obtained considering the observed flat galactic rotation curve feature, invoking the Tully-Fisher relation and assuming the presence of cold dark matter in the…

General Relativity and Quantum Cosmology · Physics 2021-07-15 Samrat Ghosh , Arunava Bhadra , Amitabha Mukhopadhyay

The long-standing issues of determination of the mass distribution and nature of the center of our Galaxy could be probed by a lensing experiment capable of testing the spatial and velocity distributions of stars nearby and beyond it. We…

Astrophysics · Physics 2009-10-31 S. Capozziello , G. Iovane

We present the basics of microlensing and give an overview of the results obtained so far. We also describe a scenario in which dark clusters of MACHOs (Massive Astrophysical Compact Halo Objects) and cold molecular clouds (mainly of $H_2$)…

Astrophysics · Physics 2009-10-31 Ph. Jetzer

Dissipative dark matter, such as mirror dark matter and related hidden sector dark matter candidates, requires an energy source to stabilize dark matter halos in spiral galaxies. It has been proposed previously that supernovae could be the…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-09 R. Foot

It has been shown by Paczy\'nski that gravitational microlensing is potentially a useful method for detecting the dark constituents of the halo of our galaxy, if their mass lies in the approximate domain $10^{-6} < M/M_{\odot} < 10^{-1}$.…

Astrophysics · Physics 2008-02-03 Philippe Jetzer

We simulated both the matter and light (galaxy) distributions in a wedge of the universe and calculated the gravitational lensing magnification caused by the mass along the line of sight of galaxies and galaxy groups identified in sky…

Astrophysics · Physics 2009-11-10 Antonio C. C. Guimarães , Adam D. Myers , Tom Shanks

We review progress in understanding dark matter by astrophysics, and particularly via the effect of gravitational lensing. Evidence from many different directions now all imply that five sixths of the material content of the universe is in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Richard Massey , Thomas Kitching , Johan Richard

Galaxy-galaxy weak lensing is a direct probe of the mean matter distribution around galaxies. The depth and sky coverage of the CFHT Legacy Survey yield statistically significant galaxy halo mass measurements over a much wider range of…

Our work is based on the stacked weak-lensing analysis of a sample of 80 strong-lensing galaxy groups. Our main results are the following: (i) the lensing signal does not allow us to firmly reject a simple singular isothermal sphere mass…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-26 G. Foëx , V. Motta , E. Jullo , M. Limousin , T. Verdugo

We study the reliability of dark-matter halo detections with three different linear filters applied to weak-lensing data. We use ray-tracing in the multiple lens-plane approximation through a large cosmological simulation to construct…

There is good evidence that most of the baryons in the Universe are dark and some evidence that most of the matter in the Universe is nonbaryonic with cold dark matter (cdm) being a promising possibility. We discuss expectations for the…

Astrophysics · Physics 2009-10-22 Evalyn Gates , Michael S. Turner

We present a study of the relation between dark matter halo mass and the baryonic content of host galaxies, quantified via luminosity and stellar mass. Our investigation uses 154 deg2 of Canada-France-Hawaii Telescope Lensing Survey…

We measure the ellipticity of isolated clusters of galaxies in the Sloan Digital Sky Survey (SDSS) using gravitational lensing. We stack the clusters, rotating so that the major axes of the ellipses determined by the positions of cluster…

Astrophysics · Physics 2011-02-11 Anna Kathinka Dalland Evans , Sarah Bridle

Dark matter is the dominant form of matter in the universe, but its nature is unknown. It is plausibly an elementary particle, perhaps the lightest supersymmetric partner of known particle species. In this case, annihilation of dark matter…

We derive the signature for condensed neutrino objects (CNOs) as the primary source of Dark Matter. Restricting our source data to minimize systematic errors, we find that by just using weak lensing data and Sunyaev-Zel'dovich data, that…

High Energy Astrophysical Phenomena · Physics 2016-08-31 P. D. Morley , D. J. Buettner

We investigate strong gravitational lensing in the concordance $\Lambda$CDM cosmology by carrying out ray-tracing along past light cones through the Millennium Simulation, the largest simulation of cosmic structure formation ever carried…

Astrophysics · Physics 2007-12-03 Stefan Hilbert , Simon D. M. White , Jan Hartlap , Peter Schneider