Integrated intensity ratio maps. (a) Integrated intensity ratio map of SiO(2–1)/CO(1–0). The black contour is drawn at 0.003 and the blue contour at 0.01. The labels 3, 6, and 7 mark the three GMCs. (b) Integrated intensity ratio map of SiO(2–1)/¹³CO(1–0). The black contour is drawn at 0.04 and the blue contour at 0.1. The gray contour is drawn at a CO/¹³CO(1–0) ratio of 15. (c) Integrated intensity ratio map of CH₃OH(2_k–1_k)/¹³CO(1–0). The black contour is drawn at 0.15 and the blue contour at 0.4. (d) Integrated intensity ratio map of SiO(2–1)/CH₃OH(2_k–1_k). The black contour is drawn at 0.5 and the blue contour at 1.