A parsec-scale flow associated with the IRAS 16547-4247 radio jet

IRAS 16547 - 4247 is the most luminous (6.2 x 10(4) L-.) embedded young stellar object known to harbor a thermal radio jet. We report the discovery using the Very Large Telescope Infrared Spectrometer and Array Camera of a chain of H-2 2.12 mum emission knots that trace a collimated flow extending over 1.5 pc. The alignment of the H-2 flow and the central location of the radio jet imply that these phenomena are intimately linked. We have also detected an isolated unresolved 12 mum infrared source toward the radio jet using TIMMI2. Our findings affirm that IRAS 16547 - 4247 is excited by a single O-type star that is driving a collimated jet. We argue that the accretion mechanism that produces jets in low-mass star formation also operates in the higher mass regime.