The WMAP results
(Spergel et al. 2003)
have given rather strict limits
on the matter and energy content of the Universe, in agreement with the
CDM model. Typically,
for 
total
= 1,
dark energy
= 0.73, and
matter
= 0.27, with
baryon
= 0.044, and
non-baryonic
= 0.23.
Some of these results depend on data from the 2dF galaxy redshift survey.
Initial results from the SDSS redshift survey are not much different
(Tegmark et al. 2003).
The ratio of baryonic to non-baryonic matter is thus
1 to ~ 5 - 6. The baryonic matter at z = 0 is mostly not in stars
(stars =
0.005), and the matter budget in e.g. the
Local Group is still not well known : there could be hot gas in
substantial amounts
(Nicastro et al. 2003).
These results further support the
CDM model for
structure formation in the Universe, and underscore the need to
understand galaxies in the framework of this theory. However, at the
scale of galaxies, the "predictions" of the
CDM model depend on
numerical simulations, which, despite their sophistication, suffer
from inadequate resolution, and may miss some of the physics.
This meeting aims to see how well specific predictions from
current cosmological simulations of dark matter halos fare on
issues such as their central density profiles,
the relation between dark to baryonic matter there, and their shape and
extent.