Joint galaxy-galaxy lensing and clustering constraints on galaxy
  formation
  We compare predictions for galaxy-galaxy lensing profiles and clustering from
the Henriques et al. (2015) public version of the Munich semi-analytical model
of galaxy formation (SAM) and the IllustrisTNG suite, primarily TNG300, with
observations from KiDS+GAMA and SDSS-DR7 using four different selection
functions for the lenses (stellar mass, stellar mass and group membership,
stellar mass and isolation criteria, stellar mass and colour). We find that
this version of the SAM does not agree well with the current data for stellar
mass-only lenses with $M_\ast > 10^{11}\,M_\odot$. By decreasing the merger
time for satellite galaxies as well as reducing the radio-mode AGN accretion
efficiency in the SAM, we obtain better agreement, both for the lensing and the
clustering, at the high mass end. We show that the new model is consistent with
the signals for central galaxies presented in Velliscig et al. (2017). Turning
to the hydrodynamical simulation, TNG300 produces good lensing predictions,
both for stellar mass-only ($\chi^2 = 1.81$ compared to $\chi^2 = 7.79$ for the
SAM), and locally brightest galaxies samples ($\chi^2 = 3.80$ compared to
$\chi^2 = 5.01$). With added dust corrections to the colours it matches the
SDSS clustering signal well for red low mass galaxies. We find that both the
SAMs and TNG300 predict $\sim 50\,\%$ excessive lensing signals for
intermediate mass red galaxies with $10.2 < \log_{10} M_\ast [ M_\odot ] <
11.2$ at $r \approx 0.6\,h^{-1}\,\mathrm{Mpc}$, which require further
theoretical development.
