Mexican Hat Gravitational Lenses
نویسندگان
چکیده
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 hat. We discuss the nonlocal e ect of shear.
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