Single-pixel spectra (black lines) of all detected molecules toward Source A. Species are given in the upper left of each panel. In all panels, the vertical blue dashed lines represent the systemic velocity obtained from C¹⁸ O (1–0). Single-peaked spectra are modeled with a Gaussian fit. The blue-skewed line profiles of CS (2–1), HCN (1–0), and HNC (1–0) are fitted with the Hill5 model (De Vries & Myers 2005). For H¹³ CN (1–0) and N₂H⁺ (1–0), the spectra are fitted with the hyperfine structure fitting subroutine in GILDAS. All fitted results are shown in red lines. The velocities of the N₂ H⁺ (1–0) hyperfine structure components are indicated by vertical red lines. In the CH₃ OH panel where the velocity is given with respect to the rest frequency (96.74138 GHz) of CH₃ OH (2₀ − 1₀ A⁺), the CH₃OH triplet around 96.74 GHz is also indicated by three vertical red lines.