Characterizing filaments in regions of high-mass star formation: High-resolution submilimeter imaging of the massive star-forming complex NGC 6334 with ArTéMiS⋆,⋆⋆
1 Laboratoire AIM, CEA/DRF–CNRS–Université Paris Diderot, IRFU/Service d’Astrophysique, C.E. Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France
2 Aix-Marseille Université, CNRS, LAM (Lab. d’Astrophysique de Marseille), UMR 7326, 13388 Marseille, France
3 Institut d’Astrophysique de Paris, Sorbonne Universités, UPMC Univ. Paris 06, CNRS, UMR 7095, 75014 Paris, France
4 European Southern Observatory, Karl Schwarzschild Str. 2, 85748 Garching bei Munchen, Germany
5 Univ. Bordeaux, LAB, UMR 5804, 33270 Floirac, France
6 I. Physik. Institut, University of Cologne, 50937 Köln, Germany
7 School of Physics & Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK
8 INAF–Osservatorio di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
Received: 24 February 2016
Accepted: 18 May 2016
Context. Herschel observations of nearby molecular clouds suggest that interstellar filaments and prestellar cores represent two fundamental steps in the star formation process. The observations support a picture of low-mass star formation according to which filaments of ~0.1 pc width form first in the cold interstellar medium, probably as a result of large-scale compression of interstellar matter by supersonic turbulent flows, and then prestellar cores arise from gravitational fragmentation of the densest filaments. Whether this scenario also applies to regions of high-mass star formation is an open question, in part because the resolution of Herschel is insufficient to resolve the inner width of filaments in the nearest regions of massive star formation.
Aims. In an effort to characterize the inner width of filaments in high-mass star-forming regions, we imaged the central part of the NGC 6334 complex at a resolution higher by a factor of >3 than Herschel at 350 μm.
Methods. We used the large-format bolometer camera ArTéMiS on the APEX telescope and combined the high-resolution ArTéMiS data at 350 μm with Herschel/HOBYS data at 70–500 μm to ensure good sensitivity to a broad range of spatial scales. This allowed us to study the structure of the main narrow filament of the complex with a resolution of 8″ or <0.07 pc at d ~ 1.7 kpc.
Results. Our study confirms that this filament is a very dense, massive linear structure with a line mass ranging from ~500 M⊙/pc to ~2000 M⊙/pc over nearly 10 pc. It also demonstrates for the first time that its inner width remains as narrow as W ~ 0.15 ± 0.05 pc all along the filament length, within a factor of <2 of the characteristic 0.1 pc value found with Herschel for lower-mass filaments in the Gould Belt.
Conclusions. While it is not completely clear whether the NGC 6334 filament will form massive stars in the future, it is two to three orders of magnitude denser than the majority of filaments observed in Gould Belt clouds, and has a very similar inner width. This points to a common physical mechanism for setting the filament width and suggests that some important structural properties of nearby clouds also hold in high-mass star-forming regions.
Key words: stars: formation / circumstellar matter / ISM: clouds / ISM: structure / ISM: individual objects: NGC 6334 / submillimeter: ISM
This publication is based on data acquired with the Atacama Pathfinder Experiment (APEX) in ESO program 091.C-0870. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory.
The final ArTéMiS+SPIRE 350 μm map (Fig. 1b) is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A54
© ESO, 2016
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.