Temperature maps using the smoothed data assuming fixed X_{p - H2CO} = 1.2 × 10^-9 and n(H₂). The maps in b) and c) are masked by signal-to-noise as in Fig. 3. The thin black contours are at a column N(H₂) = 5 × 10²² cm^-2 from the Herschel SED fit maps. a) n(H₂) = 10⁴ cm^-3, no mask b) n(H₂) = 10⁴ cm^-3c) n(H₂) = 10⁵ cm^-3. Figure E.5 shows the same figures, but with varying abundance and fixed n(H₂).