Colour temperature for the central brightest pixels (for SEDs fitted between 100 μm and 3000 μm) of the idealized filaments as a function of , which is the extinction applied to the ISRF (and the corresponding G₀ factor). The blue line shows the cylinder with A_V = 1 at the centre, green shows 5, red 10, light blue 15, and magenta 20. The true grain temperatures, T_dust, can be seen in Fig. 8.