A parsec-scale outflow from the luminous YSO IRAS 17527-2439

Joint Astronomy Centre, 660 N. Aohoku Pl., Hilo, HI - 96720, USA
e-mail: w.varricatt@jach.hawaii.edu

Received: 15 October 2010
Accepted: 17 December 2010

Abstract

Aims. We seek to understand the way massive stars form. The case of a luminous YSO IRAS 17527-2439 is studied in the infrared.

Methods. Imaging observations of IRAS 17527-2439 are obtained in the near-IR JHK photometric bands and in a narrow-band filter centred at the wavelength of the H₂ 1-0S(1) line. The continuum-subtracted H₂ image is used to identify outflows. The data obtained in this study are used in conjunction with Spitzer, AKARI, and IRAS data. The YSO driving the outflow is identified in the Spitzer images. The spectral energy distribution (SED) of the YSO is studied using available radiative transfer models.

Results. A parsec-scale bipolar outflow is discovered in our H₂ line image, which is supported by the detection in the archival Spitzer images. The H₂ image exhibits signs of precession of the main jet and shows tentative evidence for a second outflow. These suggest the possibility of a companion to the outflow source. There is a strong component of continuum emission in the direction of the outflow, which supports the idea that the outflow cavity provides a path for radiation to escape, thereby reducing the radiation pressure on the accreted matter. The bulk of the emission observed close to the outflow in the WFCAM and Spitzer bands is rotated counter clockwise with respect to the outflow traced in H₂, which may be due to precession. A model fit to the SED of the central source tells us that the YSO has a mass of 12.23 M_⊙ and that it is in an early stage of evolution.