Fit line width (FWHM) toward GMF38a. These maps show the line widths of fit components derived from the GAUSSPY+ decomposition of the spectra. If multiple components are present in a single pixel spectrum within the velocity range of the filament region, the component with the lowest peak velocity is shown. The black contours in both panels show the integrated GRS ¹³CO emission at the levels 5.0, 10.0, 20.0, and 30.0 K km s⁻¹. The contour feature at longitude ℓ = 36° is an artifact in the observational data. Top panel: Fit HISA line width. Bottom panel: Fit ¹³CO line width.