On the number of solutions of a transcendental equation arising in the theory of gravitational lensing

Abstract

The equation in the title describes the number of bright images of a point source under lensing by an elliptic object with isothermal density. We prove that this equation has at most 6 solutions. Any number of solutions from 1 to 6 can actually occur.

26 pages, 12 figures

References in corpus (1)

• Gravitational Lenses With More Than Four Images: I. Classification of Caustics

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