This work proposes an alternative way to think about gravitational lensing. Instead of assuming that weak-field spacetime geometry responds instantly to baryonic matter, it proposes that geometry needs a finite time to relax to its new configuration. From this perspective, part of the lensing signal may come from light traveling through a residual geometric “memory”: spacetime curvature that has not yet fully relaxed to the current baryonic distribution. The manuscript develops this idea and tests it with weak lensing, strong lensing, and colliding galaxy clusters.
Alejandro Rey (Thu,) studied this question.