Speaker
Description
When a massive foreground galaxy lies in front of another, more distant, background galaxy, strong gravitational lensing produces spectacular images such as Einstein rings. The detailed morphology of an Einstein ring depends not only on the gravitational field of the main deflector, but also on all the perturbations along the line of sight. As it turns out, both effects can be distinguished, so that Einstein rings may be considered “standardisable shapes”, from which the weak-lensing shear can be directly measured. In this talk, I will present a framework to include strong lensing in cosmological analyses. I will show that the associated signal is measurable with stage-IV galaxy surveys, with a very high signal-to-noise ratio, and I will present the very first forecasts on the measurements of cosmological parameters with this method.