منابع مشابه
Gravitational Lenses
Gravitational lenses are becoming a precious mean of probing the matter distribution in the Universe. From the search of matter in the Galactic halo to the study of the large-scale structures of the Universe, the gravitational lens effects offer a unique alternative to light surveys and are now widely used. This evolution is due in particular to the use of new observation devices, such as the w...
متن کاملRotation in Gravitational Lenses
Gravitational lensing deflects light. A single lens deflector can only shear images, but cannot induce rotations. Multiple lens planes can induce rotations. Such rotations can be observed in quadruply imaged sources, and can be used to distinguish between two proposed solutions of the flux anomaly problem: substructures in lensing galaxies vs large scale structure. We predict the expected amoun...
متن کاملGravitational Lenses : Recent Results
The 0, 1 and 2 derivatives of a “Fermat potential” give the three D’s of gravitational lensing: delay, deflection and distortion. Observations of these delays, deflections and distortions for doubly and quadruply imaged quasars give estimates of Hubble’s constant, H0. The single largest contribution to the uncertainty in H0 arises from the difficulty in constraining the degree of central concen...
متن کاملMexican Hat Gravitational Lenses
The mexican hat function is used to model a compensated (in density) gravitational lens. First we discuss the need for compensation. Then we integrate photon orbits to construct wavefronts. One consequence of underdensities is an o -axis caustic. We report the structure of the critical curves and caustics using the thin lens approximation, both for the mexican hat and for a perturbed mexican ha...
متن کاملInteractive Visualization of Gravitational Lenses
A tool for the interactive study of gravitational lensing is presented. Gravitational lensing is a known astrophysical phenomenon explained by means of the General Relativity Theory and it is nowadays the only scale independent method for measuring the mean matter density in the Universe. The gravitational lensing problem along with the associated physics is briefly described. The algorithm use...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1996
ISSN: 0074-1809
DOI: 10.1017/s0074180900080219