Luminous and Dark Matter Profiles from Galaxies to Clusters: Bridging the Gap with Group-scale Lenses

Understand

Observations of strong gravitational lensing, stellar kinematics, and larger-scale tracers enable accurate measures of the distribution of dark matter (DM) and baryons in massive early-type galaxies (ETGs).

• While such techniques have been applied to galaxy-scale and cluster-scale lenses, the paucity of intermediate-mass systems with high-quality data has precluded a uniform analysis of mass-dependent trends.
• With the aim of bridging this gap, we present new observations and analyses of 10 group-scale lenses at <z>=0.36 characterized by Einstein radii theta_Ein=2.5&#34;-5.1&#34; and a mean halo mass of M_200=10^14.0 Msol.
• We measure a mean concentration c_200=5.0+-0.8 consistent with unmodified cold dark matter halos.