Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dark Satellites and Cosmic Reionization   A possible explanation of the present discrepancy between the abundance of
galactic subhaloes predicted by N-Body simulations with those observed in the
Local Group is presented. We study the impact of an early reionization on the
baryonic component of the Universe using SPH simulations on group and galactic
scales. We use a simplified model for reionization described as an
instantaneous increment of the IGM temperature (with 1e5<T_{IGM}<1e6 K) at a
given redshift (z_r > 8). We find that a key role is played by compton cooling
(interaction between hot electrons and the CMB photons); at high redshift
(z_r>10) this cooling is very efficient and it is able to counteract any
heating of the gas within few Myrs. This means that a late reionization is
needed (z_r<9) to sufficiently reduce the number of luminous dwarf satellites
around our Galaxy. For a reionization redshift z_r=8 and a reionization
temperature of T_{IGM}~1e5 K we are able to reproduce the observed number of
Local Group dwarf galaxies in our simulations.

26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat