The luminosity map of M 33 produced by the “warm” dust grains. Luminosities fainter than 6 L_⊙  pc^-2 (yellow areas) are found in the outer diffuse parts of the galaxy, while higher luminosities trace the spiral arms (orange/red regions). The highest luminosity densities (>40 L_⊙   pc^-2; innermost contours; blue areas) are produced in the bright HII regions and the center of the galaxy. The “constant” interpolation method was used to estimate the “warm” dust luminosities.