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Supershells as molecular cloud factories: Parsec resolution observations of HI and 12CO(J=1-0) in GSH 287+04-17 and GSH 277+00+36
Citation
Dawson, JR and McClure-Griffiths, NM and Kawamura, A and Mizuno, N and Onishi, T and Mizuno, A and Fukui, Y, Supershells as molecular cloud factories: Parsec resolution observations of HI and 12CO(J=1-0) in GSH 287+04-17 and GSH 277+00+36, The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics, 728, (2) pp. 21. ISSN 0004-637X (2011) [Refereed Article]
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Copyright Statement
Copyright 2011 The American Astronomical Society.
DOI: doi:10.1088/0004-637X/728/2/127
Abstract
We present parsec-scale resolution observations of the atomic and molecular interstellar medium in two Galactic supershells, GSH 287+04–17 and GSH 277+00+36. H I synthesis images from the Australia Telescope Compact Array are combined with 12CO(J = 1-0) data from the NANTEN telescope to reveal substantial quantities of molecular gas closely associated with both shells. These data allow us to confirm an enhanced level of molecularization over the volumes of both objects, providing the first direct observational evidence of increased molecular cloud production due to the influence of supershells. We find that the atomic shell walls are dominated by cold gas with estimated temperatures and densities of T ~ 100 K and n 0 ~ 10 cm–3, respectively. Locally, the shells show rich substructure in both tracers, with molecular gas seen elongated along the inner edges of the atomic walls, embedded within H I filaments and clouds, or taking the form of small CO clouds at the tips of tapering atomic "fingers." We discuss these structures in the context of different formation scenarios, suggesting that molecular gas embedded within shell walls is well explained by in situ formation from the swept-up medium, whereas CO seen at the ends of fingers of H I may trace remnants of molecular clouds that pre-date the shells. A preliminary assessment of star formation activity within the shells confirms ongoing star formation in the molecular gas of both GSH 287+04–17 and GSH 277+00+36.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | evolution; ISM: atoms; ISM: bubbles; ISM: clouds; ISM: molecules; radio lines: ISM |
| Research Division: | Physical Sciences |
| Research Group: | Astronomical sciences |
| Research Field: | Galactic astronomy |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the physical sciences |
| UTAS Author: | Dawson, JR (Dr Joanne Dawson) |
| ID Code: | 75004 |
| Year Published: | 2011 |
| Web of Science® Times Cited: | 37 |
| Deposited By: | Mathematics and Physics |
| Deposited On: | 2011-12-23 |
| Last Modified: | 2012-04-13 |
| Downloads: | 0 |
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