Radial profiles of the V-band (open circles) and I-band (triangles) surface brightness (a) and integrated magnitudes (b) of Virgo UFD1. The bands represent the errors. Dashed lines in (a) represent a Sérsic law fit for each band. The effective radius and tidal radius are marked by vertical lines in (b). The radial profile of the density of detected stars shifted arbitrarily is also overlaid by filled squares in (a).