Modeling the formation and evolution of star cluster populations in
  galaxy simulations
  (Abridged) The formation and evolution of star cluster populations are
related to the galactic environment. Cluster formation is governed by processes
acting on galactic scales, and star cluster disruption is driven by the tidal
field. In this paper, we present a self-consistent model for the formation and
evolution of star cluster populations, for which we combine an N-body/SPH
galaxy evolution code with semi-analytic models for star cluster evolution. The
model includes star formation, feedback, stellar evolution, and star cluster
disruption by two-body relaxation and tidal shocks. We apply the model by
simulating a suite of 9 isolated disc galaxies and 24 galaxy mergers. The
evolutionary histories of individual clusters in these simulations are
discussed to illustrate how the environment of clusters changes in time and
space. The resulting variability of the disruption rate with time and space
affects the properties of star cluster populations. The combined effect of
clusters escaping their dense formation sites (`cluster migration') and the
preferential disruption of clusters residing in dense environments (`natural
selection') implies that the mean disruption rate of the population decreases
with cluster age. This affects the slope of the cluster age distribution, which
becomes a function of the star formation rate density. The evolutionary
histories of clusters in a galaxy merger vary widely and determine which
clusters survive the merger. This impacts the age distributions and the
locations of the surviving clusters at all times during a merger. We conclude
that accounting for the interplay between the formation, disruption, and
orbital histories of clusters enables a more sophisticated interpretation of
observed properties of cluster populations, thereby extending the role of
cluster populations as tracers of galaxy evolution.
