Fig. 4.

Sketch of the homogeneous (left) and clumpy torus (right). For the homogeneous torus, the inner side of the torus emits in NIR, the middle regions emits in MIR, and the outer side emits in FIR. For the clumpy torus, the NIR emission arises from the inner side of the directly illuminated clouds, while the MIR and FIR emission is produced from the shadowed side of the clumps (see Fig. 5). Note that clumps located at different distances can produce the same emission at a specific wavelength.