Discovering a misaligned CO outflow related to the red MSX source G034.5964-01.0292

¹ Instituto de Astronomía y Física del Espacio (IAFE), CC 67, Suc. 28, 1428 Buenos Aires, Argentina
e-mail: sparon@iafe.uba.ar
² FADU and CBC – Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina
³ Departamento de Astronomía, Universidad de Chile, Casilla 36- D Santiago, Chile

Received: 21 February 2014
Accepted: 10 June 2014

Abstract

Aims. The red MSX source G034.5964-01.0292 (MSXG34), catalogued as a massive young stellar object, was observed in molecular lines with the aim of discovering and studying molecular outflows.

Methods. We mapped a region of 3′× 3′ centred at MSXG34 using the Atacama Submillimeter Telescope Experiment in the ¹²CO J = 3–2 and HCO⁺J = 4–3 lines with an angular and spectral resolution of 22′′ and 0.11 km s^-1. Additionally, public ¹³CO J = 1–0 and near-IR UKIDSS data obtained from the Galactic Ring Survey and the WFCAM Sciencie Archive were analysed.

Results. We found that the ¹²CO spectra towards the YSO present a self-absorption dip, as is common in star-forming regions, and spectral wings that indicate outflow activity. The HCO⁺ was detected only towards the MSXG34 position at v_LSR ~ 14.2 km s^-1, in coincidence with the ¹²CO absorption dip and approximately with the velocity of previous ammonia observations. HCO⁺ and NH₃ are known to be enhanced in molecular outflows. When we analysed the spectral wings of the ¹²CO line, we discovered misaligned red- and blue-shifted molecular outflows associated with MSXG34. The near-IR emission shows a cone-like nebulosity composed of two arc-like features related to the YSO, which might be due to a cavity cleared in the circumstellar material by a precessing jet. This can explain the misalignment in the molecular outflows. From the analysis of the ¹³CO J = 1–0 data we suggest that the YSO is very likely related to a molecular clump ranging between 10 and 14 km s^-1. This suggests that MSXG34, with an associated central velocity of about 14 km s^-1, may be located in the background of this clump. Thus, the blue-shifted outflow is probably deflected by the interaction with dense gas along the line of sight. From a spectral energy distribution analysis of MSXG34 we found that its central object probably is an intermediate-mass protostar.