The following document lists the file abstract/WBRANDT_BUBBLE.abs
from catalogue VI/111.
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X-ray observations of galaxies made with the Einstein and ROSAT satellites have shown that some galaxies with powerful bursts of star formation are luminous in X-rays (e.g. Fabbiano 1989). For example, NGC 5408, a nearby extragalactic HII region galaxy which is optically less luminous than the Small Magellanic Cloud was found to have an X-ray luminosity greater than that of the whole Local Group (Stewart et al. 1982). It is bright in both the near and far infrared, and Campbell & Terlevich (1984) have deduced from infrared colors that its burst of star formation occured only about 2 Myr ago. Fabian & Ward (1993) have proposed a starburst origin for the X-rays where approximately 1000 supernovae blow a 100 pc bubble of hot gas in the ISM which radiates bremsstrahlung. IC 10 is a gas rich Local Group galaxy that is also X-ray luminous (Boller et al. 1990). Infrared and optical images show that most of its star-forming activity is concentrated in a pair of bright complexes about 1.1 kpc (3 arcmin) apart near the geometric center of the galaxy (Sandage & Tamman 1974, Hunter & Gallagher 1985, Hodge & Lee 1989). It has a large nonthermal radio source in its center which is roughly circular in shape, and Yang & Skillman (1993) suggest that this nonthermal superbubble is the result of many supernova explosions, as in NGC 5408. We propose to use ISOCAM to make maps of both NGC 5408 and IC 10 in the lines of [Ar III], [Ne II] and [Ne III]. Maps in these lines will allow us to quantify the ionization of the ISM by the violent processes occuring in these galaxies and will reveal the dusty birth and death sites of stars. We also propose to obtain an LWS full grating spectrum of NGC 5408, which has extremely strong emission lines. NGC 5408 will probably provide the best ISO template for X-ray starbursts and one of the best templates for low metalicity HII region galaxies.