The masses of satellites in GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

We use the first 100 deg(2) of overlap between the Kilo-Degree Survey and the Galaxy And Mass Assembly survey to determine the average galaxy halo mass of similar to 10 000 spectroscopically confirmed satellite galaxies in massive (M > 10(13) h(-1) M-circle dot) galaxy groups. Separating the sample as a function of projected distance to the group centre, we jointly model the satellites and their host groups with Navarro-Frenk-White density profiles, fully accounting for the data covariance. The probed satellite galaxies in these groups have total masses log < M-sub/(h(-1) M-circle dot)> approximate to 11.7-12.2 consistent across group-centric distance within the errorbars. Given their typical stellar masses, log < M-*,M-sat/(h(-2) M-circle dot)) similar to 10.5, such total masses imply stellar mass fractions of (M-*,M-sat)/(M-sub) approximate to 0.04 h(-1). The average subhalo hosting these satellite galaxies has a mass M-sub similar to 0.015M(host) independent of host halo mass, in broad agreement with the expectations of structure formation in a A cold dark matter universe.