Roulettes: A weak lensing formalism for strong lensing - II. Derivation and analysis

Understand

We present a new extension of the weak lensing formalism capable of describing strongly lensed images.

• This paper accompanies Paper I, arXiv:1603.04698 where we provided a condensed overview of the approach and illustrated how it works.
• Here we give all the necessary details, together with some more explicit examples.
• We solve the non-linear geodesic deviation equation order-by-order, keeping the leading derivatives of the optical tidal matrix, giving rise to a series of maps from which a complete strongly lensed image is formed.