First galaxy-galaxy lensing measurement of satellite halo mass in the CFHT Stripe-82 Survey

We select satellite galaxies from the galaxy group catalogue constructed with the Sloan Digital Sky Survey spectroscopic galaxies and measure the tangential shear around these galaxies with the source catalogue extracted from the Canada-France-Hawaii Telescope Stripe-82 Survey. Using the tangential shear, we constrain the mass of subhaloes associated with these satellites. The lensing signal is measured around satellites in groups with masses in the range 10¹³-5 × 10¹⁴ h^-1 M_⊙, and is found to agree well with theoretical expectations. Fitting the data with a truncated NFW profile, we obtain an average subhalo mass of log (M_sub/h^-1 M_⊙) = 11.68 ± 0.67 for satellites whose projected distances to central galaxies are in the range 0.1-0.3 h^-1 and log (M_sub/h^-1 M_⊙) = 11.68 ± 0.76 for satellites with projected halo-centric distance in [0.3, 0.5] h^-1 Mpc. The best-fitting subhalo masses are comparable to the truncated subhalo masses assigned to satellite galaxies using abundance matching and are about 5-10 times higher than the average stellar mass of the lensing satellite galaxies.