Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Fossil Phase in the Life of a Galaxy Group   We investigate the origin and evolution of fossil groups in a concordance
LCDM cosmological simulation. We consider haloes with masses between
$(1-5)\times10^{13} \hMsun$ and study the physical mechanisms that lead to the
formation of the large gap in magnitude between the brightest and the second
most bright group member, which is typical for these fossil systems. Fossil
groups are found to have high dark matter concentrations, which we can relate
to their early formation time. The large magnitude-gaps arise after the groups
have build up half of their final mass, due to merging of massive group
members. We show that the existence of fossil systems is primarily driven by
the relatively early infall of massive satellites, and that we do not find a
strong environmental dependence for these systems. In addition, we find
tentative evidence for fossil group satellites falling in on orbits with
typically lower angular momentum, which might lead to a more efficient merger
onto the host. We find a population of groups at higher redshifts that go
through a ``fossil phase'': a stage where they show a large magnitude-gap,
which is terminated by renewed infall from their environment.

8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
1
The categories of this paper are: cs
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th