Combining Size and Shape in Weak Lensing

Understand

Weak lensing alters the size of images with a similar magnitude to the distortion due to shear.

• Galaxy size probes the convergence field, and shape the shear field, both of which contain cosmological information.
• We show the gains expected in the Dark Energy Figure of Merit if galaxy size information is used in combination with galaxy shape.
• In any normal analysis of cosmic shear, galaxy sizes are also studied, so this is extra statistical information comes for free and is currently unused.