(a)–(d) Velocity-integrated maps of CO J = 1–0, ¹³CO J = 1–0, C¹⁸O J = 1–0, and CO J = 3–2, respectively. The maps are centered at the high-R_3–2/1–0 spot T15. The velocity range for integration is 77 to 177 km s⁻¹. (e) Longitude–velocity map of CO J = 3–2 emission integrated over latitudes of the V-integrated maps. (Color online)