optical lines and in the radio continuum suggests that the ionized gas is being pushed by the massive stars in Pis24, located close to the southern border of the bright region [@bohigas04]. The emission distribution at 8 $\mu$m shows PAH emission in the IRAC 8 $\mu$m band projected onto the bright  region (white area in Fig. 7).

Figure [**9**]{} displays an enlargement of this region in the IRAC bands at 3.6 (in blue), 4.5 (in green), and 8 $\mu$m (in red). The southern border of G353.2+0.9 is very bright at 4.5 and 8 $\mu$m (area in orange). Emission at 4.5 $\mu$m, detected in the southern area may originate in shocked gas. The elephant trunk detected at 172445, –341055 in optical data by Bohigas et al. (2004), which points directly towards the open cluster, radiates in the PAH features. The southern border of G353.2+0.9 and the pillar were analyzed in detail by @west10, who found kinematical evidence of strong interaction between Pis24 and the gas in the pillar. Figure 6 shows that the dust colour temperature in this region (near 172545,–3412) is higher than expected for an  region, which is compatible with a region where shock and ionization fronts are present.

