Astron. Astrophys. 343, 281-286 (1999)

(Sub)mm continuum observations of NGC 6334A

Göran Sandell

National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944, USA

Received 30 October 1998 / Accepted 9 December 1998

Abstract

We present 2 mm, 1.1 mm, 850 µm, 800 µm, and 450 µm mapping and photometry of the field surrounding NGC 6334A. We find a prominent east-west dust ridge, approximately centered on NGC 6334A. We interpret this ridge as a collimating dust disk or torus and derive a mass of 60 from our continuum data. It is possible though, that this disk-like structure is contaminated on the west-side by a protostellar source, seen as an H₂O maser. We find a second strong source MM2, near MM1 in the immediate vicinity of the HII region. H J = 4-3 spectra of MM1 and MM2 confirm that it is a separate source. MM2 approximately coincides with IRS3, a 10 µm source, which in earlier studies has been proposed to be a protostar. We estimate MM2/IRS3 to have a mass of 50 . We find two other protostellar candidates: MM3 and MM4. MM3 is a relatively compact source with a mass of 150 and connected by a ridge of dust to the HII region, while MM4 is is fainter and more extended.

We also see a thin shell of dust surrounding the red-shifted ionized outflow lobe, presumably swept up by the outflow. The dust shell has a mass of 60 . There is clearly less dust emission towards the north, and we do not see the same interaction between the ionized outflow and the surrounding molecular cloud as we see to the south.

Key words: ISM: dust, extinction ISM: H ii regions ISM: individual objects: NGC 6334A ISM: jets and outflows radio continuum: ISM submillimeter

Send offprint requests to: G. Sandell (gsandell@nrao.edu)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and data reduction
• 3. Results
  • 3.1. Morphology
  • 3.2. Deduced flux densities
• 4. Discussion
  • 4.1. A collimating disk around NGC 6334A
  • 4.2. Protostellar sources
  • 4.3. The dust shell surrounding the free-free outflow
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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