The faintest surface brightness limits of high redshift galaxies

The Low Surface Brightness (LSB) regime is the last niche for studies of galaxy formation and evolution. It is of outstanding importance for investigating not only the smallest galaxies, but also for the most massive ones. We will review the state-of-the-art of how massive galaxies progressively change their properties over cosmic time, and how LSB describes this mass assembly. Going to the deepest Hubble Space Telescope fields, we will show our latest results looking for galaxy truncations, real galaxy edges whose existence is linked with the gas density threshold for star formation. Therefore, we obtain a new physically-motivated mass-size relation, whereby massive galaxies grow by a factor of two since z = 1 while at the same time increasing by an order of magnitude their stellar density at the truncation position. The retrieval of these galaxy limits will be very beneficial for the study of stellar haloes and also for elucidating dark matter halo sizes. We will also present our future plans for improving all these results by making use of JWST and Euclid forthcoming data.