The stellar and dark halo mass assembly of galaxies
  The emerging empirical picture of galaxy stellar mass (Ms) assembly shows
that galaxy population buildup proceeds from top to down in Ms. By connecting
galaxies to LCDM halos and their histories, individual (average) Ms growth
tracks can be inferred. These tracks show that massive galaxies assembled their
Ms the earlier the more massive the halo, and that less massive galaxies are
yet actively growing in Ms, the more active the less massive is the halo. The
predicted star formation rates as a function of mass and the downsizing of the
typical mass that separate active galaxies from the passive ones agree with
direct observational determinations. This implies that the LCDM scenario is
consistent with these observations. The challenge is now to understand the
baryonic physics that drives the significant and systematical shift of the
stellar mass assembly of galaxies from the mass assembly of their corresponding
halos (from halo upsizing to galaxy downsizing).
