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Astron. Astrophys. 353, 211-226 (2000)

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Massive young stellar objects with molecular outflows *

Th. Henning 1, K. Schreyer 1, R. Launhardt 2 and A. Burkert 1

1 Astrophysikalisches Institut und Universitäts-Sternwarte, Friedrich-Schiller-Universität Jena, Schillergässchen 2-3, 07745 Jena, Germany
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

Received 22 June 1999 / Accepted 4 October 1999


We studied three members of the sample of 31 cold and luminous southern IRAS sources, which was compiled by Osterloh et al. (1997). These young stellar objects are characterized by extremely red IRAS colours [[FORMULA](100 µm) [FORMULA] [FORMULA](60 µm) [FORMULA] [FORMULA](25 µm) [FORMULA] 20[FORMULA][FORMULA](12 µm)]. Based on their strong CO line wings found in previous observations, the three objects IRAS 12091-6129, IRAS 12405-6238, and IRAS 16019-4903 were selected in order to investigate their nature and the outflow structure in more detail.

The mapping in the CO J = 2[FORMULA]1 line as well as the [FORMULA] 1.3 mm continuum dust emission show that all three sources are deeply embedded in dense cloud cores. Strong CO line wings and their mapping indicate the presence of bipolar gas outflows in all three cases.

N- and Q-band imaging resolve some substructures inside the [FORMULA] 1.3 mm maps and give evidence for deeply embedded young stellar objects which seem to drive the observed outflows. The comparison of the FIR imaging with the results in K imply that most of the K-band nebulosities are reprocessed radiation escaping through inhomogeneities in a dense cloud.

We derived physical parameters such as H2 column densities and cloud core masses from the CO and the bolometer measurements, and we compared the properties of the outflows and of the surrounding clouds with those found for well-known high-, intermediate- and low-mass objects. This comparison showed that the newly detected outflow systems belong to the most energetic outflows in our galaxy observed so far.

Key words: ISM: individual objects: IRAS 12091 – 6129, IRAS 12405 – 6238, IRAS 16019 – 4903 – ISM: jets and outflows – ISM: molecules

* Based on observations collected at the European Southern Observatory, La Silla, Chile

Send offprint requests to: Th. Henning (henning@astro.uni-jena.de)

© European Southern Observatory (ESO) 2000

Online publication: December 8, 1999