The complete figure set (175 images) is available in the online journal.

Emission lines from several molecules toward the CC core, in K (primary-beam-corrected antenna temperatures) vs. frequency (MHz). Black and red continuous lines show the data and the model whose parameters are given in Table 4. In each panel, we mark the V_LSR of the model with a vertical black line and the upper-energy level of each transition. Thick green lines indicate the section of the spectra used to get the best-fit values. In panels where the peak intensity does not reach 5σ, σ = 0.06 K, we show the ±2.5σ levels using dotted black lines. Panels (a)–(d) show CH₃OH, ³³SO, ¹³CH₃OH, and HC₃N, respectively. The CH₃OH spectrum suggests the presence of an additional and hotter component. The other emission lines toward this core and other lines of sight are available in the figure set.