Issue |
A&A
Volume 413, Number 3, January III 2004
|
|
---|---|---|
Page(s) | 939 - 948 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20031523 | |
Published online | 07 January 2004 |
Numerical simulations of expanding supershells in dwarf irregular galaxies
I. Application to Holmberg I
1
Institute of Physics, Stachki 194, Rostov-on-Don, Russia, and Isaac Newton Institute of Chile, Rostov-on-Don Branch
2
Radioastronomisches Institut der Universitt Bonn, Auf dem Hgel 71, 53121 Bonn, Germany e-mail: uklein@astro.uni-bonn.de
3
Rostov University, Sorge 5, Rostov-on-Don, Russia, and Isaac Newton Institute of Chile, Rostov-on-Don Branch e-mail: yus@phys.rsu.ru
4
CSIRO Australia Telescope National Facility, Cnr Vimiera & Pembroke Roads, Marsfield NSW 2122, Australia e-mail: Juergen.Ott@csiro.au
Corresponding author: E. I. Vorobyov, eduard_vorobev@mail.ru
Received:
14
April
2003
Accepted:
22
September
2003
Numerical hydrodynamical modelling of supernova-driven shell formation is
performed with a purpose to reproduce a giant HI ring (diameter 1.7 kpc)
in the dwarf irregular galaxy Holmberg I (Ho I). We find that the contrast in HI
surface density between the central HI depression and the ring is sensitive
to the shape of the gravitational potential. This circumstance can be used
to constrain the total mass (including the dark matter halo) of nearly
face-on dwarf irregulars. We consider two models of Ho I, which differ by
an assumed mass of the dark matter halo Mh.
The contrast in HI surface density between the central HI depression and
the ring, as well as the lack of gas expansion in the central hole,
are better reproduced by the model with a massive halo of
than by that with a small halo of
, implying that Ho I is halo-dominated.
Assuming the halo mass of
, we determine the mechanical energy
required to form the observed ring equal to
ergs,
equivalent
Type II supernovae. The inclination
of Ho I is constrained to
by comparing the modelled
HI spectrum and channel maps with those observed.
Key words: galaxies: dwarf / individual: Holmberg I=DDO 63 / ISM: bubbles
© ESO, 2004
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