Colour-colour diagrams used to select sources with excess emission due to warm dust or emission lines. Left panels: selection of sources in the centre field with Paα (cyan), H₂ (magenta), and IR (purple) excess. Middle panels: selection of sources in the northern parallel field with Paα (cyan), Brα (peach), and IR (purple) excess. Right panels: selection of sources in the southern parallel field with Paα (cyan), H₂ (4.70 µm, magenta), H₂ (2.12 µm, pale green), Brα (peach), and IR (purple) excess.