Theoretical Physics, Blackett Laboratory, Imperial College, London.
Phys Rev Lett. 2009 Oct 30;103(18):181301. doi: 10.1103/PhysRevLett.103.181301. Epub 2009 Oct 28.
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.
拓扑缺陷产生的向量微扰可以在背景星系的引力透镜中产生旋转。这是缺陷存在的一个潜在“确凿证据”，因为旋转会在弱引力透镜信号中产生一种类似卷曲的分量，而这种分量是标准密度微扰在线性阶次上不会产生的。这个旋转信号是通过宇宙弦产生的。未来的大规模弱引力透镜调查应该能够检测到这个信号，即使对于弦张力来说，它比当前的限制低一个数量级。
