Maps of primary beam corrected velocity integrated intensity (moment 0), obtained with a robustness parameter of 0.0 (Sect. 2). Data reduced with a parameter of +2.0 (close to natural weighting) do not reveal any additional features. The value 1″ corresponds to a projected linear scale of ≈19 pc. Upper left: HCN J = 1 → 0 emission with a restored beam of 2.′′71 × 1.′′ 56 and position angle PA = 43° (see the red spot in the lower left corner of the image). Contour levels are 5, 10, 20, 40, 60, and 80% of the integrated peak flux density of 24.0 Jy km s⁻¹ beam⁻¹. Upper right: H¹³CN J = 1 → 0 with a restored beam of 2.′′72 × 1.′′ 57, PA = 42°. Center, left: HC¹⁵N 1 → 0 (only V > 400 km s⁻¹) with 2.′′ 72 × 1.′′ 57, PA = 42°. Center right: CS J = 2 → 1. Contours are 5, 10, 20, 40, 60, and 80% of the integrated peak flux density of 14.1 Jy km s⁻¹ beam⁻¹. Restored beam: 2.′′57 × 1.′′ 38, PA = 41°. Lower left: C₃H₂ 2₁₂ → 1₀₁ with 2.′′ 72 × 1.′′ 57, PA = 42°. Lower right: C₃HC₂H 5₀ → 4₀. Restored beam: 2.′′72 × 1.′′ 57, PA = 42°. To convert Jy km s⁻¹ beam⁻¹ into K km s⁻¹ beam⁻¹, multiply by ≈37 (HCN), 39 (H¹³CN, HC¹⁵ N, C₃ H₂, and CH₃C₂H), or 36 (CS).