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 singular isothermal sphere to represent, respectively, the main lens galaxy and its neighbor, a faint galaxy near one of the images. Introduction. We have embarked on a project of multi-epoch observations of the quadruple images of the two gravitationally lensed objects B1422+231 and MGJ0414+0534 to compare possible structural changes in the lensed images and measure possible shifts in the relative positions of the sub-images. Here we present our images from the first epoch observations on 23 November 1997.