Tuesday

I will discuss how weak lensing by cosmic tunnels can be used to constrain modifications to General Relativity. Such modified gravity theories are very appealing since they explain the accelerated expansion of the Universe without the need for dark energy. Modified gravity manifests as a fifth force that, while screened in high density regions, is allowed to attain maximum values in under dense regions. The fifth force leads to emptier voids, which can be probed via weak lensing measurements. Even more promising is the use of weak lensing by line-of-sight tunnels, elongated regions along the line-of-sight that intersect several voids without passing through over dense regions. When applied to Dark Energy Survey mocks, tangential shear from tunnels can improve by an order of magnitude the current constraints on the Hu-Sawicki f(R) modified gravity models.