Beyond the Thin Lens Approximation
Abstract
We obtain analytic formulae for the null geodesics of FriedmannLemaîtreRobertsonWalker spacetimes with scalar perturbations in the longitudinal gauge. We use these to provide a rigorous derivation of the cosmological lens equation. We obtain an expression for the magnification of a bundle of light rays in these spacetimes without restriction to static or thin lens scenarios. We show how the usual magnification matrix naturally emerges in the appropriate limits.
 Publication:

arXiv eprints
 Pub Date:
 May 1994
 arXiv:
 arXiv:astroph/9405021
 Bibcode:
 1994astro.ph..5021P
 Keywords:

 Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 Submitted to ApJl, 9 pages plus one figure (plain TeX)