The JCMT Gould Belt Survey: A First Look at IC 5146
Abstract
We present 450 and 850 μm submillimeter continuum observations of the IC 5146 star-forming region taken as part of the James Clerk Maxwell Telescope Gould Belt Survey. We investigate the location of bright submillimeter (clumped) emission with the larger-scale molecular cloud through comparison with extinction maps, and find that these denser structures correlate with higher cloud column density. Ninety-six individual submillimeter clumps are identified using FellWalker, and their physical properties are examined. These clumps are found to be relatively massive, ranging from 0.5 {M}⊙ to 116 {M}⊙ with a mean mass of 8 {M}⊙ and a median mass of 3.7 {M}⊙ . A stability analysis for the clumps suggests that the majority are (thermally) Jeans stable, with M/{M}J< 1. We further compare the locations of known protostars with the observed submillimeter emission, finding that younger protostars, I.e., Class 0 and I sources, are strongly correlated with submillimeter peaks and that the clumps with protostars are among the most Jeans unstable. Finally, we contrast the evolutionary conditions in the two major star-forming regions within IC 5146: the young cluster associated with the Cocoon Nebula and the more distributed star formation associated with the Northern Streamer filaments. The Cocoon Nebula appears to have converted a higher fraction of its mass into dense clumps and protostars, the clumps are more likely to be Jeans unstable, and a larger fraction of these remaining clumps contain embedded protostars. The Northern Streamer, however, has a larger number of clumps in total and a larger fraction of the known protostars are still embedded within these clumps.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2017
- DOI:
- 10.3847/1538-4357/aa5b95
- arXiv:
- arXiv:1701.04898
- Bibcode:
- 2017ApJ...836..132J
- Keywords:
-
- ISM: clouds;
- ISM: structure;
- stars: formation;
- stars: protostars;
- submillimeter: galaxies;
- submillimeter: ISM;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 30 pages, 11 figures, 8 tables, accepted by ApJ