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

¹ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile e-mail: guido@das.uchile.cl
² Australia Telescope National Facility, PO Box 76, Epping 1710 NSW, Australia
³ Centro de Radioastronomía y Astrofísica, UNAM, Apdo. Postal 3-72, Morelia, Michoacán, 58089, México
⁴ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁵ European Southern Observatory, Casilla 19001, Santiago, Chile
⁶ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Received: 30 March 2006
Accepted: 16 November 2006

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 ~18´´.

Methods.The observations were made using the Atacama Pathfinder Experiment Telescope in the  transitions of ¹²CO and ¹³CO,  transitions of HCO⁺ and H¹³CO⁺, and transition of CS.

Results.Our observations reveal the presence of a collimated bipolar outflow with lobes ~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°, has a semi-opening angle of 14°, and in which the gas moves outwards with a constant total velocity, with respect to the cone apex, of ~120 km s^-1. The outflow is massive and energetic (flow mass ~110 ; mass outflow rate ~  yr^-1; momentum ~  km s^-1 and kinetic energy ~ erg), and has a dynamical time scale of  yr. These parameters are consistent with the flow being driven by a young massive stellar object with  .