The red curves in the four panels represent the filament skeleton. (a) The background shows the number of Gaussian components of the ¹²CO spectra, with contours indicating the integrated intensity of ¹²CO in the range of 18 to 160 K km s⁻¹, with a step size of 5 K km s⁻¹. The integration velocity range is 0–20 km s⁻¹, which is consistent across panels (b), (c), and (d). The beam size is shown in the bottom left corner, and the scale length of 10 pc is shown in the bottom right corner. (b) The background shows the number of Gaussian components of the ¹³CO spectra, with contours showing the integrated intensity of ¹³CO ranging from 3 to 49 K km s⁻¹, with a step size of 1.2 K km s⁻¹. (c) The background shows the number of Gaussian components of the C¹⁸O spectra, with contours showing the integrated intensity of C¹⁸O ranging from 0.5 to 7 K km s⁻¹, with s step size of 1 K km s⁻¹. (d) The background shows the optical depth of ¹³CO, with the same contours as in panel (b).