Recursion relations for gravitational lensing

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Date

2019

Journal Title

Journal ISSN

Volume Title

Publisher

Springer Nature

Abstract

The weak gravitational lensing formalism can be extended to the strong lensing regime by integrating a nonlinear version of the geodesic deviation equation. The resulting ‘roulette’ expansion generalises the notion of convergence, shear and flexion to arbitrary order. The independent coefficients of this expansion are screen space gradients of the optical tidal tensor which approximates to the usual lensing potential in the weak field limit. From lensed images, knowledge of the roulette coefficients can in principle be inverted to reconstruct the mass distribution of a lens. In this paper, we simplify the roulette expansion and derive a family of recursion relations between the various coefficients, generalising the Kaiser–Squires relations beyond the weak-lensing regime.

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Keywords

Gravitational lensing, Roulette formalism, Recursion relations, Weak-lensing regime

Citation

Normann, B.D., Clarkson, C. Recursion relations for gravitational lensing. Gen Relativ Gravit 52, 28 (2020).