Oral Presentation
On the formation and physical properties of the intracluster light in hierarchical galaxy formation models
Presenter: Emanuele Contini (Yonsei Univeristy)
We study the formation of the Intra-Cluster Light (ICL) using a semi-analytic
model of galaxy formation, coupled to merger trees extracted from N-body simulations of
groups and clusters. We assume that the ICL forms by (1) stellar stripping of
satellite galaxies and (2) relaxation processes that take place during galaxy
mergers. The fraction of ICL in groups and clusters predicted by our models
ranges between 10 and 40 per cent, with a large halo-to-halo scatter and no
halo mass dependence.
We note, however, that our predicted ICL fractions depend on the resolution:
for a set of simulations with particle mass one order of magnitude larger than
that adopted in the high resolution runs used in our study, we find that the predicted
ICL fractions are ~30-40 per cent larger than those found in the high resolution runs.
On cluster scale, large part of the scatter is due to a range of dynamical
histories, while on smaller scale it is driven by individual
accretion events and stripping of very massive satellites, $M_{*} \gtrsim
10^{10.5} M_{\odot}$, that we find to be the major contributors to the ICL.
The ICL in our models forms very late (below $z\sim 1$), and a fraction varying
between 5 and 25 per cent of it has been accreted during the hierarchical
growth of haloes. In agreement with recent observational measurements, we find
the ICL to be made of stars covering a relatively large range of
metallicity, with the bulk of them being sub-solar.
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