Exploring the low surface brightness (LSB) universe is one of the most challenging tasks in the era of the deep imaging and spectroscopic surveys. 
It is however a crucial ingredient to map the mass assembly of galaxies at all scales and all environments and thus constrain their formation within the Lambda-Cold Dark Matter paradigm. 
In this framework, clusters of galaxies are expected to grow over time by accreting smaller groups. During the infall process, the material stripped from the galaxy outskirts builds up the stellar halos and the intracluster light (ICL; see e.g. Contini et al. 2014; Cui et al. 2014; Pillepich et al. 2018). These are diffuse and very faint (μg > 26 mag/arcsec2) components made of stars stripped from satellite galaxies, also in the form of streams and tidal tails, with multiple stellar population and complex kinematics, which are still growing at the present epoch. 

VEGAS science goals

1. to map the light distribution and colors out to 8-10 Re and down to the faint surface brightness levels of μg ≃ 31 mag/arcsec2, μr ≃ 28 mag/arcsec2; μi ≃ 27 mag/arcsec2
2. to study of the galaxy structure and its faint stellar halo, including the diffuse light component, inner substructures as signatures of recent cannibalism events, inner disks and bars
   
3. detection of the external low-surface brightness structures in galaxies, like tidal tails, stellar streams and shells and study the connection with environment
   
4. for galaxies in the local universe (D<50 Mpc), to census and study the globular clusters and galaxy satellites in the outermost regions of the host galaxy 
5. the full sample proposed for VEGAS will provide essential statistical constraints on theoretical models and enable discrimination among competing galaxy formation theories

Ongoing VEGAS projects