Journal Article

The ‘Carina Flare’ supershell: probing the atomic and molecular ISM in a Galactic chimney

J. R. Dawson, N. Mizuno, T. Onishi, N. M. McClure-Griffiths and Y. Fukui

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 387, issue 1, pages 31-44
Published in print June 2008 | ISSN: 0035-8711
Published online May 2008 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2008.13152.x
The ‘Carina Flare’ supershell: probing the atomic and molecular ISM in a Galactic chimney

More Like This

Show all results sharing this subject:

  • Astronomy and Astrophysics

GO

Show Summary Details

Preview

The ‘Carina Flare’ supershell, GSH 287+04−17, is a molecular supershell originally discovered in12CO(J= 1–0) with the NANTEN 4 m telescope. We present the first study of the shell's atomic ISM, using H i 21-cm line data from the Parkes 64-m telescope Southern Galactic Plane Survey. The data reveal a gently expanding, ∼230 × 360 pc H i supershell that shows strong evidence of Galactic Plane blowout, with a break in its main body atz∼ 280 pc and a capped high-latitude extension reachingz∼ 450 pc. The molecular clouds form comoving parts of the atomic shell, and the morphology of the two phases reflects the supershell's influence on the structure of the ISM. We also report the first discovery of an ionized component of the supershell, in the form of delicate, streamer-like filaments aligned with the proposed direction of blowout. The distance estimate to the shell is re-examined, and we find strong evidence to support the original suggestion that it is located in the Carina Arm at a distance of 2.6 ± 0.4 kpc. Associated H i and H2 masses are estimated asMH I≈ 7 ± 3 × 105M and , and the kinetic energy of the expanding shell asEK∼ 1 × 1051 erg. We examine the results of analytical and numerical models to estimate a required formation energy of several 1051 to ∼1052 erg, and an age of ∼107 yr. This age is compatible with molecular cloud formation time-scales, and we briefly consider the viability of a supershell-triggered origin for the molecular component.

Keywords: ISM: atoms; ISM: bubbles; ISM: evolution; ISM: molecules; ISM: structure; Galaxy: structure

Journal Article.  10809 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.