Extraction of the continuum for the spectrum integrated over the entire slit length. The dashed line represents the observed spectrum, the green disks represent the sample values for continuum measurement, and the solid line is the fitted fourth-degree polynomial. The uncertainty on the adjusted continuum is displayed in blue. The location of the emission lines is shown in green, and the location of absorption lines is shown in red (some cannot be shown in this figure because they are visible only in specific regions).