Left: Spatial profile along the dispersion axis in the blue channel. The bottom panel shows the QSO profile, and the middle one shows the galaxy+QSO profile. The arrow points to the location of the asymmetry. The dashed line is a mirror image of the profile, which emphasizes the asymmetry. We attribute the slight asymmetry of the galaxy+QSO profile to the emission from the galaxy. The top panel shows the result of the subtraction of the shifted and scaled QSO template from the galaxy+QSO profile. Right: Spatial profile of the subtracted spectrum with three different scale factors. The bottom panel shows the best result, in which the count level at the position of the gap (arrow) matches the level of the overall background (scale = 1.8). In the middle panel the scale factor is smaller than the best scale factor, and the count level in the gap is above the level of the background (scale = 1.6). As a result, the extracted spectrum is dominated by the QSO. This situation is reversed in the top panel, in which the QSO is oversubtracted (scale = 1.9).