The Sloan Lens ACS Survey. XII. Extending Strong Lensing to Lower Masses

Understand

We present observational results from a new Hubble Space Telescope (HST) Snapshot program to extend the methods of the Sloan Lens ACS (SLACS) Survey to lower lens-galaxy masses.

• We discover 40 new galaxy-scale strong lenses, which we supplement with 58 previously discovered SLACS lenses.
• In addition, we determine the posterior PDFs of the Einstein radius for 33 galaxies (18 new and 15 from legacy SLACS data) based on single lensed images.
• We find a less-than-unity slope of $0.64\pm0.06$ for the $\log_{10} {\sigma}_*$-$\log_{10} {\sigma}_{\rm SIE}$ relation, which corresponds to a 6-$\sigma$ evidence that the total mass-density profile of early-type galaxies varies systematically in the sense of being shallower at higher lens-galaxy velocity dispersions.