  One of the major challenges in modern astrophysics is to understand the
origin and the evolution of galaxies, the bright, massive early type galaxies
(ETGs) in particular. Therefore, these galaxies are likely to be good probes of
galaxy evolution, star formation and, metal enrichment in the early Universe.
In this context it is very important to set up a diagnostic tool able to
combine results from chemo-dynamical N-Body-TSPH (NB-TSPH) simulations of ETGs
with those of spectro-photometric population synthesis and evolution so that
all key properties of galaxies can be investigated. The main goal of this paper
is to provide a preliminary validation of the software package before applying
it to the analysis of observational data. The galaxy models in use where
calculated by the Padova group in two different cosmological scenarios: the
SCDM, and the Lambda CDM. For these models, we recover their
spectro-photometric evolution through the entire history of the Universe. We
computed magnitudes and colors and their evolution with the redshift along with
the evolutionary and cosmological corrections for the model galaxies at our
disposal, and compared them with data for ETGs taken from the COSMOS and the
GOODS databases. Starting from the dynamical simulations and photometric models
at our disposal, we created synthetic images from which we derived the
structural and morphological parameters. The theoretical results are compared
with observational data of ETGs selected form the SDSS database. The simulated
colors for the different cosmological scenarios follow the general trend shown
by galaxies of the COSMOS and GOODS. Within the redshift range considered, all
the simulated colors reproduce the observational data quite well.
