Weak lensing distortions beyond shear

Understand

When a luminous source is extended, its distortions by weak gravitational lensing are richer than a mere combination of magnification and shear.

• In a recent work, we proposed an elegant formalism based on complex analysis to describe and calculate such distortions.
• The present article further elaborates this finite-beam approach, and applies it to a realistic cosmological model.
• In particular, the cosmic correlations of image distortions beyond shear are predicted for the first time.