# The JCMT Gould Belt Survey: A First Look at IC 5146

## TL;DR

This study presents submillimetre observations of IC 5146, identifying dense clumps, analyzing their stability, and examining the relationship between protostars and these clumps to understand star formation conditions.

## Contribution

It provides the first detailed submillimetre survey of IC 5146, characterizing clump properties, stability, and protostar correlations within different star-forming regions.

## Key findings

- Most clumps are thermally Jeans stable.
- Younger protostars are strongly associated with submillimetre peaks.
- The Cocoon Nebula has a higher fraction of dense, unstable clumps with protostars.

## Abstract

We present 450 and 850 micron submillimetre continuum observations of the IC5146 star-forming region taken as part of the JCMT Gould Belt Survey. We investigate the location of bright submillimetre (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 submillimetre clumps are identified using FellWalker and their physical properties are examined. These clumps are found to be relatively massive, ranging from 0.5to 116 MSun with a mean mass of 8 MSun and a median mass of 3.7 MSun. A stability analysis for the clumps suggest that the majority are (thermally) Jeans stable, with M/M_J < 1. We further compare the locations of known protostars with the observed submillimetre emission, finding that younger protostars, i.e., Class 0 and I sources, are strongly correlated with submillimetre 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 IC5146: 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.