Spectral line shapes of four tracers depicted in filament G37. The spectra contours of ¹²CO, ¹³CO, and C¹⁸O (3–2) are represented by the blue, yellow, and red lines, respectively, within each block (30ʺ × 30ʺ). The velocity range for these lines is from 47 to 65 km s⁻¹. The background displays the intensity map of ¹³CO (3–2) at a velocity range of [47,65] km s⁻¹. The right panels display the spectral lines of the large semicircle (LSC) and small semicircle (SSC), which cover the region shown in the left panel. The central velocities of the Hα RRL lines, indicated by the green cross in the left panel, are marked by dotted vertical lines. Each spectral line is distinguished by its respective color.