Spatial distribution of species that can be related to PDR chemistry. For C₂H and CN, the contours correspond to the 30%, 40%, 60%, and 80% of the maximum line intensity. For CO⁺ and HCO the contours correspond to the 45%, 60%, and 80% of the maximum line intensity. The different percentages used for the contour levels for the CO⁺ and HCO integrated intensities is due to the lower signal-to-noise of these species compared to C₂H and CN.