Weak Gravitational Lensing of Finite Beams.
- Fleury P Départment de Physique Théorique, Université de Genève, 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
- Larena J Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, South Africa.
- Uzan JP Institut d'Astrophysique de Paris, CNRS UMR 7095, Université Pierre et Marie Curie-Paris VI, 98 bis Boulevard Arago, 75014 Paris, France, and Sorbonne Universités, Institut Lagrange de Paris, 98 bis Boulevard Arago, 75014 Paris, France.
- 2017-12-09
Published in:
- Physical review letters. - 2017
English
The standard theory of weak gravitational lensing relies on the infinitesimal light beam approximation. In this context, images are distorted by convergence and shear, the respective sources of which unphysically depend on the resolution of the distribution of matter-the so-called Ricci-Weyl problem. In this Letter, we propose a strong-lensing-inspired formalism to describe the lensing of finite beams. We address the Ricci-Weyl problem by showing explicitly that convergence is caused by the matter enclosed by the beam, regardless of its distribution. Furthermore, shear turns out to be systematically enhanced by the finiteness of the beam. This implies, in particular, that the Kaiser-Squires relation between shear and convergence is violated, which could have profound consequences on the interpretation of weak-lensing surveys.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1103/PhysRevLett.119.191101
- PMID 29219481
- Persistent URL
- https://sonar.ch/global/documents/29077
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