Normalised histograms of the effective radius (in parsecs, assuming a distance of 20.7 Mpc), ellipticity and F606W magnitude of different samples of sources; N is the number of sources in each bin and N_max the maximum of their respective histograms. The grey histogram shows all the sources of the catalogues in grey (446 sources), the red hatched histogram the 20 spectroscopically confirmed GCs and the blue histogram the sources which fulfil the selection criteria (128 sources). The vertical dashed lines indicate the ranges of the GC selection, in each of the parameters.