Upper panel: Two single-Gaussian profiles fit to the Hα emission line. The red curve shows the fit after masking the artifacts (marked by the red bands), while the blue curve displays the result when the artifacts are not masked. Bottom: Fitting residuals, where the gray shading denotes the 1σ uncertainty of the spectrum. In both cases, the sky-line regions are masked out, as indicated by the blue bands. The mean (μ_G), standard deviation (σ_G), and FWHM_G (corrected for the instrument resolution of 39.377 km s⁻¹) of the fit are listed in the plot.