LABOCA 870 micron dust continuum mapping of selected infrared-dark cloud regions in the Galactic plane

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.

23 pages, 14 figures, and 6 tables. Accepted for publication in Astronomy and Astrophysics

References in corpus (28)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• The Large APEX Bolometer Camera LABOCA
• Kinematic Distances to Molecular Clouds identified in the Galactic Ring Survey
• Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
• IR Dust Bubbles: Probing the Detailed Structure and Young Massive Stellar Populations of Galactic HII Regions
• The Bolocam Galactic Plane Survey IV: 1.1 and 0.35 mm Dust Continuum Emission in the Galactic Center Region
• A SCUBA imaging survey of ultracompact HII regions: The environments of massive star formation
• Supersonic turbulence, filamentary accretion,and the rapid assembly of massive stars and disks
• Outflows from Massive YSOs as Seen with the Infrared Array Camera
• Probing the initial conditions of High Mass Star formation -- I. Deuteration and depletion in high mass pre/protocluster clumps
• Search for starless clumps in the ATLASGAL survey
• Clump Lifetimes and the Initial Mass Function
• A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
• Spitzer IRAC Detection and Analysis of Shocked Molecular Hydrogen Emission
• Resolving distance ambiguities towards 6.7 GHz methanol masers
• Deuterium fractionation and the degree of ionisation in massive clumps within infrared dark clouds
• A (sub)millimetre study of dense cores in Orion B9
• A molecular line study of the filamentary infrared dark cloud G304.74+01.32
• Deuterium Fractionation as an Evolutionary Probe in Massive Proto-stellar/cluster Cores
• Massive star formation in the GMC G345.5+1.0: Spatial distribution of the dust emission
• Emission Mechanism of "Green Fuzzies" in High-mass Star Forming Regions

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• The Lifetimes of Phases in High-Mass Star-Forming Regions
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• Gravitational instability of filamentary molecular clouds, including ambipolar diffusion
• The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study
• 13CO and C18O J=2-1 mapping of the environment of the Class 0 protostellar core SMM 3 in Orion B9
• High-resolution images of two wiggling stellar jets, MHO 1502 and MHO 2147, obtained with GSAOI+GeMS
• CO observations and investigation of triggered star formation towards N10 infrared bubble and surroundings
• 870 micron continuum observations of the bubble-shaped nebula Gum 31
• The Seahorse Nebula: New views of the filamentary infrared dark cloud G304.74+01.32 from SABOCA, Herschel, and WISE
• A detailed study of the high-mass clump interacting with the bubble N10
• Star forming regions linked to RCW78 and the discovery of a new IR bubble
• Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament