Different quantities with [C ii] emission in units of K km s^-1 in contours: I_FIR tracing the UV radiation field re-radiated in the FIR by dust particles, I_{8 μm} tracing the UV radiation field by fluorescence of PAHs, I_{CO (1 − 0)} tracing the molecular gas, τ₁₆₀ tracing the dust column, I_Hα emitted by ionized gas, and, finally, the ratio I_{[ C ii ]}/I_FIR. All maps are convolved to 36″ spatial resolution and re-gridded to a pixel size of 14″, that of the SPIRE 500 μm map.