Abundance map of SiO, computed by comparing the column densities of SiO and H₂. SiO abundance in gray scale with black contours (contour levels from 7 × 10^-10 to 47 × 10^-10 by 10 × 10^-10). The red contour shows the SiO column density at 1.5 × 10¹³ cm^-2, which is equivalent to the 5σ level and helps to estimate the uncertainty of the map. The two crosses indicate the positions of the two main continuum peaks. For more information on the abundance see Appendix A.