Temperature maps derived from the HCN-to-HNC ratio at 30″ with IRAM-30 m (see Paper I). The fields with I(HNC) < 2 K km s⁻¹ have been masked. The black contours show I(N₂H⁺) ≥ 2.5 K km s⁻¹, three times the noise estimated from the emission-free sub-regions in the maps. Same as in Fig. 1, cyan triangles are the protostellar objects while the yellow and white stars are the O-B stars, respectively.