AAS 205th Meeting, 9-13 January 2005
Session 142 Galactic Structure, Halo and High Velocity
Poster, Thursday, January 13, 2005, 9:20am-4:00pm, Exhibit Hall

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[142.12] HI Gas Associated with Superbubbles - the Invisible Component of their Kinetic Energies

B. C. Dunne, Y.-H. Chu (University of Illinois), L. Staveley-Smith (Australia Telescope National Facility), R. A. Gruendl (University of Illinois)

Superbubbles are large (~100 pc across) shells in the interstellar medium (ISM) created by the combined action of stellar winds and supernova explosions of massive stars in an OB association. The shell of swept-up gas is ionized and heated to ~104 K by the UV flux of the OB stars in the association, but the ionized gas shell may be surrounded by a co-expanding HI shell if the ionization front is trapped within the superbubble shell. The energy injected into the ISM by the massive stars is reclaimed as both thermal and kinetic energies in comparable amounts. Further, a majority of energy reclaimed as kinetic energy in the expansion of the superbubble is found to be in the neutral HI gas shell. Therefore, to obtain a complete measurement of the energies stored in superbubbles, we must survey their neutral HI gas shells. Here, we report HI 21-cm line observations of thirteen superbubbles in the Large Magellanic Cloud made with the Australia Telescope Compact Array and the Parkes Observatory radio telescopes. These observations are used to estimate the HI masses and kinetic energies associated with the superbubbles for a comprehensive investigation of superbubble energetics.

The author(s) of this abstract have provided an email address for comments about the abstract: carolan@astro.uiuc.edu

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© 2004. The American Astronomical Society.