Speaker
Description
One of the cornerstones of the standard model of cosmology is the assumption that, on large scales, the Universe is homogeneous and isotropic. Some dark energy and modified gravity models, however, naturally lead to large-scale anisotropies. Thus, it is of great importance to test this broad assumption. One possible method of probing these anisotropies involves the use of weak gravitational lensing. More specifically, the imprints that these anisotropies would have on the weak shear of light beams on cosmological scales could be analysed in upcoming surveys like Euclid, SKA, and LSST. We outline how we applied the perturbative formalism developed by Pitrou et al. (arXiv:1503.01125,1503.01127) in order to estimate the magnitude of $B$-mode shear generated in the weak lensing signal by large-scale, late-time anisotropic expansion. We examine the possibility of using tomographic lensing in order to break the degeneracy between anisotropic expansion histories. Finally, we investigate how coupling between non-linearities and anisotropic expansion may affect observed $B$-mode power spectra.
