Discovery of an energetic bipolar molecular outflow towards IRAS 16547-4247

Abstract

Aims. We present molecular line observations of the molecular core associated with IRAS 16547-4247, which have allowed us to determine its physical and kinematical properties at angular resolutions of similar to 18".

Methods. The observations were made using the Atacama Pathfinder Experiment Telescope in the J = 3 -> 2 transitions of (12)CO and (13)CO, J = 4 -> 3 transitions of HCO(+) and H(13)CO(+), and J = 7 -> 6 transition of CS.

Results. Our observations reveal the presence of a collimated bipolar outflow with lobes similar to 0.7 pc in extent and aligned with the thermal jet located at the center of the core. The morphology and velocity structure of the flow are well described by a biconical outflow that is inclined from the line of sight by an angle of 84 degrees, has a semi-opening angle of 14 degrees, and in which the gas moves outwards with a constant total velocity, with respect to the cone apex, of similar to 120 km s(-1). The outflow is massive and energetic (flow mass similar to 110 M(circle dot); mass outflow rate similar to 2 x 10(-2) M(circle dot) yr(-1); momentum similar to 2 x 10(3) M(circle dot) km s(-1) and kinetic energy similar to 9 x 10(47) erg), and has a dynamical time scale of 6 x 10(3) yr. These parameters are consistent with the flow being driven by a young massive stellar object with L(bol) similar to 6 x 10(4) L(circle dot).