a) Continuum emission of W3 IRS5 region at 353.6 GHz (black contours) overplotted with the NICMOS 2.22 μm emission (color scale). The synthesized beam size is , PA − 14°. The contour levels are –3, 3, 5, 7, ..., 19, 23, 27, ... σ with 1σ of 10 mJy beam^-1. The red crosses mark the positions of the five point sources derived from the visibility fit. The red open squares are the positions of near-infrared sources identified by Megeath et al. (2005) while the red filled circles represent the positions of cm-wave sources from van der Tak et al. (2005). b) Vector-averaged 353.6 GHz continuum visibilities. The red filled circles with error bars are the observed data. The expected zero amplitude is shown as a dashed histogram. The model consisting of five point sources is plotted with open blue squares.