Disruption of satellite galaxies in simulated groups and clusters: the
  roles of accretion time, baryons, and pre-processing
  We investigate the disruption of group and cluster satellite galaxies with
total mass (dark matter plus baryons) above 10^10 M_sun in the Hydrangea
simulations, a suite of 24 high-resolution cosmological hydrodynamical zoom-in
simulations based on the EAGLE model. The simulations predict that ~50 per cent
of satellites survive to redshift z = 0, with higher survival fractions in
massive clusters than in groups and only small differences between baryonic and
pure N-body simulations. For clusters, up to 90 per cent of galaxy disruption
occurs in lower-mass sub-groups (i.e., during pre-processing); 96 per cent of
satellites in massive clusters that were accreted at z < 2 and have not been
pre-processed survive. Of those satellites that are disrupted, only a few per
cent merge with other satellites, even in low-mass groups. The survival
fraction changes rapidly from less than 10 per cent of those accreted at high z
to more than 90 per cent at low z. This shift, which reflects faster disruption
of satellites accreted at higher z, happens at lower z for more massive
galaxies and those accreted onto less massive haloes. The disruption of
satellite galaxies is found to correlate only weakly with their pre-accretion
baryon content, star formation rate, and size, so that surviving galaxies are
nearly unbiased in these properties. These results suggest that satellite
disruption in massive haloes is uncommon, and that it is predominantly the
result of gravitational rather than baryonic processes.
