Evolution of star clusters in a cosmological tidal field
  We present a method to couple N-body star cluster simulations to a
cosmological tidal field, using the Astrophysical Multipurpose Software
Environment. We apply this method to star clusters embedded in the CosmoGrid
dark matter-only LambdaCDM simulation. Our star clusters are born at z = 10
(corresponding to an age of the Universe of about 500 Myr) by selecting a dark
matter particle and initializing a star cluster with 32,000 stars on its
location. We then follow the dynamical evolution of the star cluster within the
cosmological environment.
  We compare the evolution of star clusters in two Milky-Way size haloes with a
different accretion history. The mass loss of the star clusters is continuous
irrespective of the tidal history of the host halo, but major merger events
tend to increase the rate of mass loss. From the selected two dark matter
haloes, the halo that experienced the larger number of mergers tends to drive a
smaller mass loss rate from the embedded star clusters, even though the final
masses of both haloes are similar. We identify two families of star clusters:
native clusters, which become part of the main halo before its final major
merger event, and the immigrant clusters, which are accreted upon or after this
event; native clusters tend to evaporate more quickly than immigrant clusters.
Accounting for the evolution of the dark matter halo causes immigrant star
clusters to retain more mass than when the z=0 tidal field is taken as a static
potential. The reason for this is the weaker tidal field experienced by
immigrant star clusters before merging with the larger dark matter halo.
