Procedure used to remove the broad high-velocity SiO emission from the datacubes. Top: example of the line fitting of a spectrum where both broad and narrow emission exist (corresponding to the blue spectrum of CygX-N3 shown in Fig. A.2). The two Gaussian fits are shown in green (for the broad component) and blue (for the narrow component). The red line shows the sum of the two Gaussian components. Bottom: same spectrum as the top panel, here with the respective broad Gaussian fit subtracted.