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LABOCA 870 μm dust continuum mapping of selected infrared-dark cloud regions in the Galactic plane
- Source :
- Astronomy & Astrophysics. 542:A101
- Publication Year :
- 2012
- Publisher :
- EDP Sciences, 2012.
-
Abstract
- We have mapped four selected about 0.5 deg x 0.5 deg-sized fields containing Spitzer 8-micron dark regions with APEX/LABOCA at 870 micron. Selected positions in the fields were observed in C17O(2-1) to obtain kinematic information. The obtained LABOCA maps are used in conjunction with the Spitzer IR images. The total number of clumps identified in this survey is 91, out of which 40 (44%) appear dark at 8 and 24 micron. The remaining clumps are associated with mid-IR emission. Many of the identified clumps are massive enough to allow high-mass star formation, and some of them already show clear signposts of that. Seven clumps associated with extended-like 4.5 micron emission are candidate extended green objects (EGOs). Filamentary dust "ridges" were found towards the Spitzer bubbles N10/11 in one of our fields, which conforms to the triggered high-mass star formation in the system. The relative number of IR-dark and IR-bright clumps suggest that the duration of the former stage is about 1.6x10^5 yr. The mass distribution of the total sample of clumps, and that separately constructed for the IR-dark and IR-bright clumps, could be fitted at the high-mass end with the power-law function dN/dlogM ~ M^(-0.8...-0.7). The C17O observation positions appear to be dominated by non-thermal motions, and the data also revealed some potential sites of strong CO depletion. In G11.36+0.80, which is the best example of a filamentary IRDC in our sample, the clumps appear to be gravitationally bound. The fragmentation of the filament can be understood in terms of a "sausage"-type fluid instability, in agreement with the results for other IRDCs. The formation of filamentary IRDCs might be caused by converging turbulent flows, and the same process may play a role in exciting the fluid perturbations responsible for the fragmentation of the clouds into clumps.<br />Comment: 23 pages, 14 figures, and 6 tables. Accepted for publication in Astronomy and Astrophysics
- Subjects :
- Physics
Mass distribution
Star formation
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Galactic plane
Astrophysics - Astrophysics of Galaxies
01 natural sciences
Instability
Protein filament
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
0103 physical sciences
Infrared dark cloud
010306 general physics
010303 astronomy & astrophysics
Subjects
Details
- ISSN :
- 14320746 and 00046361
- Volume :
- 542
- Database :
- OpenAIRE
- Journal :
- Astronomy & Astrophysics
- Accession number :
- edsair.doi.dedup.....af197117e73b82450dbfbee37bd16617