Entering uncharted territory: the extremely low surface brightness Universe
Current state-of-the-art imaging surveys deliver images with limiting surface brightness of 26.5 mag/arcsec^2. This depth is around 100 times fainter than the brightness of the sky in professional observatories. This view of the Universe is the basis of most of our visual understanding of the closest (galactic and extragalactic) objects. However, going deeper is absolutely mandatory if we want to understand a plethora of astrophysical phenomena that manifest themselves at lower surface brightness limits. To understand from the smallest scales of our local Galactic cirrus to the huge extensions of the intra-cluster light of massive galaxy clusters I will present in this talk two important steps forward conducted here at the IAC. The first one is The IAC Stripe82 Legacy Project: a public survey for the astronomical community which includes 275 square degrees in 5 optical bands reaching 28.5 mag/arcsec^2 depth. The second one is the deepest ever imaging of the nearby Universe: 8h of GTC time on the near UGC00180 galaxy reaching a limiting surface brightness of 31.5 mag/arcsec^2 (100 times deeper than traditional surveys). A large amount of unexpected discoveries emerge in these unprecedented set of images.