First PC, which explains 92.29% of the variance. The tomogram is plotted to the left and the eigenspectrum to the right. White means stronger correlation, and black means anticorrelation. The 3σ contour of the CH₂NH 4₁₃–3₁₂ transition is plotted in black. The vertical dotted lines represent the redshifted rest frequencies of the detected CH₂NH transitions, the vertical dashed lines show the redshifted rest frequencies of the ground-state c-C₃H₂, HCN, and HCO⁺ lines, and the vertical dashed-dotted lines represent the redshifted rest frequencies of the HCN-vib and HC₃N-vib lines. The two lines on either side of the CH₂NH 6–5 transition are unlabeled and correspond to c-C₃H₂ transitions J = 7 − 6 and a doublet of J = 6 − 5 transitions.