Extremely high velocity gas from the massive young stellar objects in IRAS 17233-3606

¹ ESO, Karl-Schwarzschild Strasse 2, 85748 Garching-bei-München, Germany e-mail: sleurini@eso.org
² INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
³ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁴ Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany

Received: 29 June 2009
Accepted: 21 August 2009

Abstract

Context. Molecular outflows from high-mass young stellar objects provide an excellent way to study the star formation process, and investigate if they are scaled-up versions of their low-mass counterparts.

Aims. We selected the nearby massive star forming region IRAS 17233-3606 in order to study the kinematics and physics along the molecular outflow(s) originating from this source.

Methods. We observed IRAS 17233-3606 in CO, a typical tracer of gas associated with molecular outflow, with the Submillimeter Array in the (2-1) transition, and with the APEX telescope in the higher excitation (6–5) line. Additional infrared H₂ observations were performed with the UKIRT telescope. The CO data were analysed using a LVG approach.

Results. Our data resolve the previously detected molecular outflow into at least three different components, one of them with a high collimation factor (~4), and characterised by emission at extremely high velocities | > 120 km s^-1). The estimate of the kinematical outflow parameters are typical of massive YSOs, and in agreement with the measured bolometric luminosity of the source. The kinematic ages of the flows are in the range 10²–10³ yr, and therefore point to young objects that still have not reached the main sequence.