State-of-the art of semianalytic models (Sofia Cora, UNLP)

Semi-analytic models of galaxy formation and evolution (SAMs) are a
powerful method to study how galaxies form and evolve within
individual dark matter halos in a CDM cosmogony, the latter being
provided by N-body simulations or by analytical methods like the
extended Press-Schechter theory. SAMs incorporates the physical
processes that affect the baryonic component, such as gas cooling,
star formation and feedback, with the advantage of reaching a larger
dynamic range than fully selfconsistent hydro-simulations at a far
smaller computational cost. Most of the SAMs developed by different
research groups in the past decade constrain the free parameters
involved in the modelization of the different physical processes with
a set of global properties of the galaxy population at low redshift,
like the luminosity function, the Tully-Fisher relation, the
colour-magnitude relation, and measures of abundance and clustering as
a function of the physical properties of galaxies, among others. Model
results must be also consistent with the galaxy population at earlier
times. However, ultra-deep surveys are just beginning to provide
convincing results for the general galaxy population at high
redshifts. On the other hand, galaxy group catalogues constitute a
complementary tool to constraint model assumptions in detail. They
have been recently constructed from the application of halo-based
group finder to the Sloan Digital Sky Survey Data, which has the
ability to split the galaxy population in central and satellite
galaxies. The different properties of these two types of galaxies
clearly reveals the different processes to which they are subjected
and the influence of the environment. Thus, matching such a wealth of
data is a great challenge for any galaxy formation model. The degree
of agreement and the discrepancies found allow to asses how
realistically SAMs treat the astrophysics of galaxy formation. I will
present the state-of-art of current SAMs, focusing on those properties
of the galaxy population that are not properly reproduced, which give
hints of the astrophysical processes that still need better
understanding.