Palla, & Ho 2000; Bally & Zinnecker 2005) are important. A small number of B-type young stars have been found to be associated with collimated outflows and possibly even circumstellar disks (see Garay & Lizano 1999; Arce et al. 2007; Cesaroni et al. 2007). The source IRAS 16547-4247 is the best example of a highly-collimated outflow associated with an O-type protostar studied so far, and its study may reveal important information about the way high mass stars form.

The systemic LSR velocity of the ambient molecular cloud where IRAS 16547-4247 is embedded is $-$30.6 km s$^{-1}$ (Garay et al. 2007). Adopting the galactic rotation model of Brand & Blitz (1993) and assuming that the one-dimensional rms velocity dispersion among molecular clouds is 7.8 km s$^{-1}$ (Stark & Brand 1989), we estimate a distance of 2.9$\pm$0.6 kpc for the source. IRAS 16547-4247 has a bolometric luminosity of 6.2$\times$10$^4$ $L_\odot$, equivalent to that of a single O8 zero-age main-sequence star, although it is probably a cluster for which the most massive star would have slightly lower luminosity. Garay et al. (2003) detected an embedded triple radio continuum source associated with the IRAS 16547-4247. The three radio components are aligned in a northwest-southeast 