Mergers, tidal interactions, and mass exchange in a population of disc
  globular clusters: II. Long-term evolution
  Globular clusters (GCs), the oldest stellar systems observed in the Milky
Way, have for long been considered single stellar populations. As such, they
provided an ideal laboratory to understand stellar dynamics and primordial star
formation processes. However, during the last two decades, observations
unveiled their real, complex nature. Beside their pristine stars, GCs host one
or more helium enriched and possibly younger stellar populations whose
formation mechanism is still unknown. Even more puzzling is the existence of
GCs showing star by star iron spreads. Using detailed N-body simulations we
explore the hypothesis that these anomalies in metallicity could be the result
of mutual stripping and mergers between a primordial population of disc GCs. In
the first paper of this series we proved, both with analytical arguments and
short-term N-body simulations, that disc GCs have larger fly-by and close
encounter rates with respect to halo clusters. These interactions lead to mass
exchange and even mergers that form new GCs, possibly showing metallicity
spreads. Here, by means of long-term direct N-body simulations, we provide
predictions on the dynamical properties of GCs that underwent these processes.
The comparison of our predictions with available and future observational data
could provide insights on the origin of GCs and on the Milky Way build-up
history as a whole.
