Doubling Strong Lensing as a Cosmological Probe

Understand

Strong gravitational lensing provides a geometric probe of cosmology in a unique manner through distance ratios involving the source and lens.

• This is well known for the time delay distance derived from measured delays between lightcurves of the images of variable sources such as quasars.
• Recently, double source plane lens systems involving two constant sources lensed by the same foreground lens have been proposed as another probe, involving a different ratio of distances measured from the image positions and fairly insensitive to the lens modeling.
• Here we demonstrate that these two different sets of strong lensing distance ratios have strong complementarity in cosmological leverage.