Rotation of galaxies as a signature of cosmic strings in weak lensing surveys

TL;DR

This paper proposes that galaxy rotations caused by cosmic strings could serve as a distinctive signature in weak lensing surveys, enabling detection of such topological defects at lower tensions than previously possible.

Contribution

It introduces a method to identify cosmic strings through their unique rotation signature in weak lensing data, which is not produced by standard density perturbations.

Findings

Rotation signals can be detected in future surveys.

Detection possible for string tensions below current limits.

Rotation generates a curl component in weak lensing maps.

Abstract

Vector perturbations sourced by topological defects can generate rotations in the lensing of background galaxies. This is a potential smoking gun for the existence of defects since rotation generates a curl-like component in the weak lensing signal which is not generated by standard density perturbations at linear order. This rotation signal is calculated as generated by cosmic strings. Future large scale weak lensing surveys should be able to detect this signal even for string tensions an order of magnitude lower than current constraints.