ArTéMiS imaging of the filamentary infrared dark clouds G1.75-0.08 and G11.36+0.80: Dust-based physical properties of the clouds and their clumps

Abstract

We imaged the infrared dark clouds (IRDCs) G1.75-0.08 and G11.36+0.80 at 350 $\mu$m and 450 $\mu$m using the ArTéMiS bolometer. These data were used in conjunction with our previous 870 $\mu$m observations with the Large APEX BOlometer CAmera (LABOCA). The clumps in G11.36+0.80 were also observed in the N${}_2$H${}^{+}(1-0)$ transition with the IRAM 30-metre telescope. G1.75-0.08 was found to be composed of two cold ($\sim 14.5$ K), massive (several $\sim 10^3$ M${}_{\odot }$) clumps that are projectively separated by $\sim 3.7$ pc. Both clumps are 70 $\mu$m dark, but they do not appear to be bounded by self-gravity. The G1.75-0.08 filament was found to be subcritical by a factor of $\sim 14$ with respect to its critical line mass. G11.36+0.80 was found to be moderately (by a factor of $\sim 2$) supercritical and composed of four clumps. The dust temperatures of the clumps are $\sim 13-15$ K, and their masses are in the range $\sim 232-633$ M${}_{\odot }$. All the clumps are gravitationally bound. The projected, average separation of the clumps is $\sim 1$ pc. A configuration that is observed in G1.75-0.08, namely two clumps at the ends of the filament, could be the result of gravitational focussing acting along the cloud. The two clumps fulfil the mass-radius threshold for high-mass star formation. Owing to the location of G1.75-0.08 near the Galactic centre ($\sim 270$ pc), environmental effects such as a high level of turbulence, tidal forces, and shearing motions could affect the cloud dynamics. The observed clump separation in G11.36+0.80 can be understood in terms of a sausage instability. The G11.36+0.80 clumps do not lie above the mass-radius threshold for high-mass star formation. The substructure observed in one of the clumps in G11.36+0.80 suggests that the IRDC has fragmented in a hierarchical fashion. This conforms to the filamentary paradigm for Galactic star formation.

16 pages (incl. two appendices), 8 figures, 10 tables, accepted for publication in A&A, abstract abridged for arXiv

References in corpus (30)

• Theory of Star Formation
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Structural Analysis of Molecular Clouds: Dendrograms
• Star formation through gravitational collapse and competitive accretion
• The Large APEX Bolometer Camera LABOCA
• Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
• The link between turbulence, magnetic fields, filaments, and star formation in the Central Molecular Zone cloud G0.253+0.016
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• A 24 Micron Point Source Catalog of the Galactic Plane from Spitzer/MIPSGAL
• On the frequency of N2H+ and N2D+
• 'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016
• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• Aspect Ratio Dependence of the Free-Fall Time for Non-Spherical Symmetries
• Galactocentric variation of the gas-to-dust ratio and its relation with metallicity
• Investigating the structure and fragmentation of a highly filamentary IRDC
• Investigating the Global Collapse of Filaments Using Smoothed Particle Hydrodynamics
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Jeans Fragmentation and Cluster Formation
• Probing fragmentation and velocity sub-structure in the massive NGC 6334 filament with ALMA
• Formation of the Musca filament: Evidence for asymmetries in the accretion flow due to a cloud-cloud collision
• Distributed Low-Mass Star Formation in the IRDC G34.43+00.24
• Star formation in 'the Brick': ALMA reveals an active proto-cluster in the Galactic centre cloud G0.253+0.016
• Distance biases in the estimation of the physical properties of Hi-GAL compact sources-I. Clump properties and the identification of high-mass star forming candidates
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions-IX. A pilot study towards IRDC G034.43+00.24 on multi-scale structures and gas kinematics
• The chemical structure of young high-mass star-forming clumps: (II) parsec-scale CO depletion and deuterium fraction of $\mathrm{HC}{\mathrm{O}}^{+}$
• Edge collapse and subsequent longitudinal accretion in Filament S242
• The origin of a universal filament width in molecular clouds
• The ArTéMiS wide-field submillimeter camera: preliminary on-sky performances at 350 microns
• Modeling Turbulence in Galactic Centers
• On filament fragmentation and the impact of ambient environment on it
• Dense cores in the Seahorse infrared dark cloud: physical properties from modified blackbody fits to the far-infrared-submillimetre spectral energy distributions

Cited by in corpus (1)

• Comparison of Herschel and ArTéMiS observations of massive filaments