Fig. 6.

LVG calculations. We assumed N(SO)=2×10¹³ cm⁻², N(H₂CO)=1×10¹³ cm⁻², and N(C¹⁸O)= 2×10¹⁶ cm⁻². From top to bottom, we plot the I(SO J=5₆→4₅)/I(C¹⁸O J=2→1), I(SO J=5₆→4₅)/I(H₂CO J=3_0,3→2_0,2), and I(H₂CO J=3₀₃ →2₀₂)/I(C¹⁸O J=2→1) line intensity ratios. The long-dashed line corresponds to a gas kinetic temperature of T_k=30 K, which is the midplane temperature derived by Piétu et al. (2005) and Pacheco-Vázquez et al. (2015). Solid lines indicate the values derived from our maps (Fig. 5). The red and blue lines trace the maximum and minimum observed ratios, respectively.