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The recent study of the strong gravitational lens ESO 325-G004 [1] leads to a new possibility for testing General Relativity and its extensions. Such gravity lens observational studies can be instrumental for establishing a limitation on…

General Physics · Physics 2018-11-07 V. G. Gurzadyan , A. Stepanian

Current X-ray observations and simulations show that gravitational lensing can be used to infer the structure near the event horizons of black holes, constrain the dynamics and evolution of black-hole accretion and outflows, test general…

High Energy Astrophysical Phenomena · Physics 2019-04-04 George Chartas , Henric Krawczynski , David Pooley , Richard F. Mushotzky , Andrew J. Ptak

We present a novel test of general relativity (GR): measuring the geometric component of the time delay due to gravitational lensing. GR predicts that photons and gravitational waves follow the same geodesic paths and thus experience the…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 David Rubin , Istvan Szapudi , Benjamin J. Shappee , Gagandeep S. Anand

Weak gravitational lensing is a unique probe of the dark side of the universe: it provides a direct way to map the distribution of dark matter around galaxies, clusters of galaxies and on cosmological scales. Furthermore, the measurement of…

Astrophysics · Physics 2010-01-07 Henk Hoekstra , Bhuvnesh Jain

We consider a machine learning algorithm to detect and identify strong gravitational lenses on sky images. First, we simulate different artificial but very close to reality images of galaxies, stars and strong lenses, using six different…

Instrumentation and Methods for Astrophysics · Physics 2021-04-06 H. G. Khachatryan

Weak gravitational lensing, the correlated distortion of background galaxy shapes by foreground structures, is a powerful probe of the matter distribution in our universe and allows accurate constraints on the cosmological model. In recent…

Weak gravitational lensing is a very sensitive way of measuring cosmological parameters, including dark energy, and of testing current theories of gravitation. In practice, this requires exquisite measurement of the shapes of billions of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 G. Nurbaeva , F. Courbin , M. Gentile , G. Meylan

We describe methods applied to the final photometric reductions and calibrations to the standard system of the images collected during the third phase of the Optical Gravitational Lensing Experiment survey - OGLE-III. Astrometric reduction…

Astrophysics · Physics 2008-07-25 A. Udalski , M. K. Szymanski , I. Soszynski , R. Poleski

This course presents some applications of gravitational lensing to the measurement of masses of galaxies (galaxy-galaxy lensing, Eintein rings, perturbations of giant arcs) and cluster of galaxies (strong and weak lensing). This complements…

Astrophysics · Physics 2007-05-23 Y. Mellier

Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still…

Upcoming deep optical surveys, such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), will scan the sky to unprecedented depths, detecting billions of galaxies. However, this amount of detections will lead to the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-04 Manon Ramel , Cyrille Doux , Marine Kuna

Gravitational lensing directly measures mass density fluctuations along the lines of sight to very distant objects. No assumptions need to be made concerning bias, the ratio of fluctuations in galaxy density to mass density. Hence, lensing…

Astrophysics · Physics 2007-05-23 Joachim Wambsganss , Renyue Cen , Jeremiah P. Ostriker

Recent developments in gravitational lensing astronomy have paved the way to genuine mappings of the gravitational potential at cosmological scales. We stress that comparing these data with traditional large scale structure surveys will…

High Energy Physics - Phenomenology · Physics 2009-10-31 Jean-Philippe Uzan , Francis Bernardeau

A gravitational lens (GL)-search program, initiated in 1990 at the Nordic Optical Telescope (NOT), has revealed several possible GL-candidates among a sample of 168 quasars (QSOs), chosen from three lists compiled by C. Hazard, D. Reimers…

Astrophysics · Physics 2016-08-30 A. O. Jaunsen , M. Jablonski , B. R. Pettersen , R. Stabell

Weak gravitational lensing of distant galaxies by foreground structures has proven to be a powerful tool to study the mass distribution in the universe. Nowadays, attention has shifted from clusters of galaxies to the statistical properties…

Astrophysics · Physics 2009-11-07 Henk Hoekstra , Howard Yee , Mike Gladders

Gravitational lenses can provide crucial information on the geometry of the Universe, on the cosmological scenario of formation of its structures as well as on the history of its components with look-back time. In this review, I focus on…

Astrophysics · Physics 2009-10-31 Y. Mellier

The four observables associated with gravitational lensing of distant quasars by intervening galaxies: image splittings, relative amplifications, time delays, and optical depths, provide separate measures of the strength of the…

Astrophysics · Physics 2009-08-18 Lawrence Krauss , Martin White

The field of weak gravitational lensing, which measures the basic properties of the Universe by studying the way that light from distant galaxies is perturbed as it travels towards us, is a very active field in astronomy. This short article…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-17 Adam Amara

Gravitational lensing of very high energy photons has recently been observed in the JVAS B0218+357 strong lensing system. This observation opens the possibility of performing a test of gravity at high energy by comparing the difference in…

High Energy Astrophysical Phenomena · Physics 2019-04-11 J-F. Glicenstein

In paper I of this series (Fosalba et al. 2013), we presented a new N-body lightcone simulation from the MICE collaboration, the MICE Grand Challenge (MICE-GC), containing about 70 billion dark-matter particles in a (3 Gpc)^3 comoving…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-30 P. Fosalba , E. Gaztanaga , F. J. Castander , M. Crocce