Distribution map of the identified galaxies, in the fore and background (left) and in the cluster (right). The galaxies are overplotted on an HST-RGB image, consisting of the F435W (blue), F606W (green), and F814W (red) filters from the FF programme. In the left panel, the background galaxies are shown with red circles, while foreground objects are shown with blue circles. In the right panel, squares correspond to passive cluster galaxies, while stars indicate active cluster galaxies, where their classification is based on the presence or absence of optical emission lines. The galaxies have been coloured according to their velocity relative to the cluster (z = 0.3475), with bluer colours meaning higher velocities towards us, and redder colours corresponding to higher velocities away from us, see also the colour bar on the right.