the dust absorption efficiency ($\kappa_\nu\ \propto\ \nu^n$). We adopted $\kappa_\nu$ = 40 cm$^2$ g$^{-1}$, a value derived from the expressions by @hildebrand83. Dust temperatures range from $\sim$25 to $\sim$50 K, with the highest values close to G353.2+0.9, in agreement with previous results from @persi86. The region of low dust temperatures at 172515, –3418, encircled by regions with higher temperatures, coincides with the eastern section of the cavity of G353.12+0.86. Dust linked to the W arm of the large shell has a dust temperature of 30 K, while values as high as 50 K were derived for the environs of G353.2+0.9. Regions with high T$_c$ far from Pis24 (for example G353.1+0.6) are suggestive of the existence of unknown excitation sources [[@damke06]]{}.

The derived dust temperatures are typical for  regions. A comparison with the optical image shows that areas with high dust temperature coincide with bright H$\alpha$ or radio continuum emitting regions. This behaviour is compatible with the fact that the stellar UV radiation field of the massive stars in the region is responsible for the heating of the interstellar dust.

Fig. \[IR-2\] displays a composite image of the brightest areas of NGC6357 using the IRAC images: 3.6 $\mu$m is in blue, 