Astron. Astrophys. 358, 242-256 (2000)

(Sub)mm continuum mapping of NGC 6334 I & I(N)

A cobweb of filaments and protostars

G. Sandell

National Radio Astronomy Observatory ^*, P.O. Box 2, Green Bank, WV 24944, USA (gsandell@nrao.edu)

Received 7 June 1999 / Accepted 16 March 2000

Abstract

We present high resolution (sub)mm continuum maps obtained with the bolometer UKT14 on the JCMT of the high mass star formation complex NGC 6334 I and I(N), the latter also known as Gezari's cold source (Gezari 1982). The maps at 1.1 mm and 800 µm cover the whole northern part of the NGC 6334 complex ( 5´ 8´), while the coverage is more limited at 450 µm and 350 µm and centered on NGC 6334 I(N).

The strongest dust emission at all wavelengths originates from a compact source near or coincident with the Ultracompact HII - region NGC 6334 F and the FIR-source and hot core region NGC 6334 I. The dust in NGC 6334 I is hot, T_d 100 K, and we derive a total mass (gas + dust) of 200 . We resolve Gezari's cold source into a compact (deconvolved FWHM 10 ") dust source, which appears optically thick even at 1.1 mm. I(N) is embedded in a dense cloud core, 2.5´ 1.5 ´, with a mass of 2200 . I(N) is clearly a high-mass Class 0 object . It emits a large fraction of its luminosity in the sub-mm (L_bol 1.7 10⁴ ), it drives a molecular outflow and coincides with a CH₃OH maser, suggesting that I(N) has already formed a hot accretion disk. We derive a total mass of 250-400 , corresponding to an average gas density 1.6-2.6 10⁷ cm^-3 and a line of sight visual extinction of 2000^m, rendering it impossible to detect I(N) even in the thermal or mid-IR.

We also find eight additional compact sub-mm sources. Some of these are probable high-to-intermediate mass protostars, some may be massive cold starless cloud cores that eventually will collapse to form stars. Our sub-mm maps also show a remarkable narrow, lumpy, linear filament, which has no optical or near-IR counterpart. This filament bounds the dust emission to the west and is at least 7´ (3.5 pc) in length with a width of 15 "-20 ". It breaks up into dense condensations with a separation of 3-4 times the width of the filament.

Key words: ISM: dust, extinction ISM: H ii regions ISM: jets and outflows ISM: individual objects: NGC 6334 I

* The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and data reduction
  • 2.1. Observations
  • 2.2. Data reduction
• 3. Results
  • 3.1. Large scale morphology
  • 3.2. The linear filament
  • 3.3. Cores, ridges and holes
  • 3.4. Compact sources
• 4. Simple analysis of the dust emission
  • 4.1. NGC 6334 I
  • 4.2. NGC 6334 I(N)
  • 4.3. Other sources and total cloud mass
• 5. Discussion
  • 5.1. The formation of a high mass cluster
  • 5.2. The strong sub-mm sources NGC 6334 I, I(N) and SM 2
  • 5.3. The new sub-mm sources
  • 5.4. The linear filament
• 6. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 26, 2000
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