Three images (a,b,c) of source 21 are shown over the color image of the cluster. The insets show the deep RGB composite (F105W + F125W + F140W + F160W,  F814W,  F435W + F606W) of the multiple images. Image 21a is currently not covered by spectroscopy, however, we rely on the fact it is the only source with photometric redshift (z_phot = 5.36), which is consistent with the spectroscopic one (z = 5.109) within an area of 10″ × 10″ from the predicted position provided by the lens model (1.2″ away from the source 21a (ID(ASTRODEEP) = 678). On the right, the F814W images (negative blue) with superimposed Lyα contours (red) at 2 and 4σ are shown with the SED-fitting performed with ASTRODEEP photometry. The peak of the Lyα emission is nearly located on top of clump 21.4b and 21.4c.