Simplified galaxy formation with mesh-less hydrodynamics
  Numerical simulations have become a necessary tool to describe the complex
interactions among the different processes involved in galaxy formation and
evolution, unfeasible via an analytic approach. The last decade has seen a
great effort by the scientific community in improving the sub-grid physics
modelling and the numerical techniques used to make numerical simulations more
predictive. Although the recently publicly available code GIZMO has proven to
be successful in reproducing galaxy properties when coupled with the model of
the MUFASA simulations and the more sophisticated prescriptions of the Feedback
In Realistic Environments (FIRE) set-up, it has not been tested yet using
delayed cooling supernova feedback, which still represent a reasonable approach
for large cosmological simulations, for which detailed sub-grid models are
prohibitive. In order to limit the computational cost and to be able to resolve
the disc structure in the galaxies we perform a suite of zoom-in cosmological
simulations with rather low resolution centred around a sub-L* galaxy with a
halo mass of $3\times 10^{11}\,\rm M_\odot$ at $z=0$, to investigate the
ability of this simple model, coupled with the new hydrodynamic method of
GIZMO, to reproduce observed galaxy scaling relations (stellar to halo mass,
stellar and baryonic Tully-Fisher, stellar mass-metallicity and mass-size). We
find that the results are in good agreement with the main scaling relations,
except for the total stellar mass, larger than that predicted by the abundance
matching technique, and the effective sizes for the most massive galaxies in
the sample, which are too small.
