Gravitational lensing formalism in a curved arc basis: A continuous description of observables and degeneracies from the weak to the strong lensing regime

Understand

Gravitationally lensed curved arcs provide a wealth of information about the underlying lensing distortions.

• Extracting precise lensing information from extended sources is a key component in many studies aiming to answer fundamental questions about the Universe.
• To maintain accuracy with increased precision, it is of vital importance to characterize and understand the impact of degeneracies inherent in lensing observables.
• In this work, we present a formalism to describe the gravitational lensing distortion effects resulting in curved extended arcs based on the eigenvectors and eigenvalues of the local lensing Jacobian and their directional differentials.