Ratio of the T_MB temperatures of ¹²CO 3–2/¹²CO 6–5. From top to bottom; left hand column shows IRAS 4A red outflow knots I4A-R2, I4A-R1, central source, blue outflow knots I4A-B1, I4A-B2 and IRAS 4B central source positions. Coordinates of these positions are given in Table 2. The spectra are binned to 0.6 km s^-1. The blue and red masks under the spectra in the left column show the range is used for the ratio calculations. Right hand column shows the ratios of these transitions.