13-18 December 2015
International Conference Centre Geneva
Europe/Zurich timezone

Effects of the second-order vector mode on weak lensing signals

17 Dec 2015, 17:38
3m
Level -1, Room 16 (International Conference Centre Geneva)

Level -1, Room 16

International Conference Centre Geneva

17 Rue de Varembé, 1211 Geneva

Speaker

Mr Shohei Saga (Naogya university)

Description

Vector mode of cosmological perturbation theory imprints characteristic signals on the weak lensing signals such as curl- and B-modes which are never imprinted by the scalar mode. However, the vector mode is neglected in the standard first-order cosmological perturbation theory since it only has a decaying mode. This situation changes if the cosmological perturbation theory is expanded up to second order. The second-order vector and tensor modes are inevitably induced by the product of the first-order scalar modes. We study the effect of the second-order vector mode on the weak lensing curl- and B-modes. We find that the curl-mode induced by the second-order vector mode is comparable to that induced by the primordial gravitational waves with the tensor-to-scalar ratio $r = 0.1$ at $\ell \approx 200$. In this case, the curl-mode induced by the second-order vector mode dominates at $\ell > 200$. Furthermore, the B-mode cosmic shear induced by the second-order vector mode dominates on almost all scales. However, we find that the observational signatures of the second-order vector and tensor modes cannot exceed the expected noise of ongoing and upcoming weak lensing measurements. We conclude that the curl- and B-modes induced by the second-order vector and tensor modes are unlikely to be detected in future experiments.

Primary author

Mr Shohei Saga (Naogya university)

Co-authors

Dr Daisuke Yamauchi (The University of Tokyo) Dr Kiyotomo Ichiki (Nagoya university)

Presentation Materials