Fabian Walter, PASA, 16 (1), 106
The html and gzipped postscript versions of this paper are in preprint form.
To access the final published version, download the pdf file.
Next Section: On Holes and Shells | Contents Page: Volume 16, Number 1 |
The Violent Interstellar Medium of Nearby Dwarf Galaxies
Fabian Walter
Radioastronomisches Institut, Bonn, GermanyE-mail: walter@astro.uni-bonn.de
Abstract:
High resolution H I observations of nearby dwarf galaxies (most of which are situated in the M81 group at a distance of about 3.2Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M31 and M33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's gravitational potential. The origin of these features is still a matter of debate. In general, young star forming regions (OB-associations) are held responsible for their formation. This picture, however, is not without its critics and other mechanism such as the infall of high velocity clouds, turbulent motions or even gamma ray bursters have been recently proposed. Here I will present one example of a supergiant shell in IC2574 which corroborates the picture that OB associations are indeed creating these structures. This particular supergiant shell is currently the most promising case to study the effects of the combined effects of stellar winds and supernova-explosions which shape the neutral interstellar medium of (dwarf) galaxies.
Keywords: galaxies: individual (IC 2574, Holmberg II, DDO 47, NGC 3077), ISM: kinematic and dynamics, ISM: structure, radio lines: ISM, X-rays: ISM
- On Holes and Shells in Galaxies
- Holes in Dwarfs vs. Holes in Spirals
- So, what created the holes?
- The case of the Supergiant shell in IC2574
- Conclusions
- Acknowledgements
- References
б© Copyright Astronomical Society of Australia 1997
ASKAP
Public