ISF as seen in different types of emission. Panel (a): Column density map of H₂ (N(H₂)) obtained from dust opacity Herschel+Planck observations at 850 µm (Lombardi et al. 2014). The white contours correspond to [10²², 5 × 10²², 10²³] cm⁻², and the blue contour represents the footprint of our IRAM-30m observations. Panel (b): N₂H⁺ (1–0) integrated-intensity map of observed with IRAM-30m at a resolution of 30″ (see Hacar et al. 2017, for additional information). Panel (c): Kinetic temperature of the gas (T_K) obtained from observations of the two inversion transitions NH₃ (1,1) and NH₃ (2,2) at 32″ with the GBT (Friesen et al. 2017). The white and yellow stars represent the B- and O-type stars in the region, respectively, as in Fig. 1, panel (b).