Gravitational Lenses and VLBI Structures

Vlbi Imaging of the Gravitational Lenses

We present wide-field images of the quadruple gravitational lenses B1422+231 and MGJ0414+0534 obtained from global Very Long Baseline Interferometry (VLBI) observations at 8.4GHz on 23 November 1997. We present also a lens model for MGJ0414+0534, which reproduces the core positions and flux densities of the VLBI images, combining a singular isothermal ellipsoid with external shear, and a singul...

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...

Finding and Modelling Gravitational Lenses

Rotation 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...

Gravitational 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...