Orateur
Description
Weak gravitational lensing distorts shapes and brightnesses, introducing correlations in the apparent ellipticities of galaxies, and enabling constraints on cosmological parameters such as Omega_m and sigma_8. Strong gravitational lenses are also subject to weak lensing perturbations, leaving a measurable imprint in the form of line-of-sight (LOS) shear. Stage-IV photometric galaxy surveys are on track to detect more than 100 000 strong gravitational lenses, and these could be used as a novel cosmological observable via the correlations between the LOS shear and itself, galaxy positions and galaxy shapes.
In this talk, I will present the current status of this project, detailing how the LOS shear manifests in strong lensing images, the new correlation functions defined by this observable, and the sources of uncertainty affecting the detectability of these correlations. Considering various scenarios for the stage-IV strong-lensing samples, I will show that the correlation signal will be detectable with a high signal-to-noise ratio even in a pessimistic scenario, and carries great promise for adding statistical power and mitigating systematics in standard 3x2pt analysis.