Azimuthal brightness profiles at (left) t = 0 yr and (right) t = 10⁷ yr, taken along radial flux peaks in the images of the belt with e_b = 0.4. Wavelengths are (top to bottom) 1200 ?m (in red), 160 ?m (in blue), and 24 ?m (in black). Solid lines stand for images PSF-broadened with Gaussians with FWHMs of 8.5″, 9.7″, 5.7″, in the same order. This illustrates apocentre glow at long wavelengths as suggested by Pan et al. (2016). The dashed lines stand for unsmoothened images.