Stellar halos from deep VST surveys: comparing observations and theory

In the recent years, a big effort was made to develop deep photometric surveys aimed at studying galaxy structures down to the faintest levels of surface brightness of mu_g~27-30 mag/arcsec^2 .
In this context, the VST Early-type GAlaxies Survey (VEGAS) is producing competitive results. Therefore, taking advantage of the deep photometry, we can address the build up history of the stellar halo by comparing the surface brightness profile and the stellar mass fraction with the prediction of cosmological galaxy formation. One of the priority science goals of VEGAS is to study the faint outer regions of the massive galaxies in groups and clusters. The deep observations can be directly compared with the predictions from the up-to-date theories for the stellar halo formation and the relation with the galaxy environment.
In this talk, I will review the main results on the study of galaxy stellar halos of ETGs by using both VEGAS and FDS deep images.