Fig. 5. Continuum emission at 15.5 µm  (contours) superimposed on the AIB 6.2 µm  map (grey scale). The continuum flux was taken to be the average of the flux on each side of the [Ne III ]15.5 µm  line. The 6.2 µm  feature strength was estimated as explained in the Appendix C. The contours are from 10 to 80 Jy/pixel (1 pixel = ), by steps of 5 Jy/pixel; the grey scale map spans 0.01 to 0.3 erg s^{- 1} cm^-2 sr^-1. The position of  Ori A is indicated by a cross.