Parity Dependence in Strong Lens Systems as a Probe of Dark Matter Substructure

Understand

The amount of mass in small, dark matter clumps within galaxies (substructure) is an important test of cold dark matter.

• One approach to measuring the substructure mass fraction is to analyze the fluxes of images that have been strongly lensed by a galaxy.
• Flux ratios between images that are anomalous with respect to smooth (no substructure) models have previously suggested that there is a greater amount of substructure than found in dark matter simulations.
• One measure of anomalous flux ratios is parity dependence -- that the fluxes of different images of a source are perturbed differently.