Issue |
A&A
Volume 376, Number 1, September II 2001
|
|
---|---|---|
Page(s) | 98 - 111 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20010997 | |
Published online | 15 September 2001 |
The neutral hydrogen content of Fornax cluster galaxies
1
Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
2
School of Physics, University of Melbourne, Victoria 3010, Australia
3
Hamburger Sternwarte, Gojenbergsweg 112, 20119 Hamburg, Germany
Corresponding author: A. Schröder, anja@obs-nice.fr
Received:
7
March
2001
Accepted:
5
July
2001
We present a new set of deep Hi observations of member
galaxies of the Fornax cluster. We detected 35 cluster
galaxies in Hi. The resulting sample, the most comprehensive
to date, is used to investigate the distribution of neutral hydrogen
in the cluster galaxies.
We compare the Hi content of the detected cluster galaxies
with that of field galaxies by measuring Hi mass-to-light
ratios and the Hi deficiency parameter of Solanes et al.
([CITE]). The mean Hi mass-to-light ratio of the
cluster galaxies is , significantly lower than for a
sample of Hi-selected field galaxies (
),
although not as low as in the Virgo cluster (
).
In addition, the Hi content of two cluster galaxies
(NGC 1316C and NGC 1326B) appears to have been
affected by interactions. The mean Hi deficiency for the
cluster is
(for galaxy types
),
significantly greater than for the field sample (
). Both
these tests show that Fornax cluster galaxies are
Hi-deficient compared to field galaxies. The kinematics of the
cluster galaxies suggests that the Hi deficiency may be caused
by ram-pressure stripping of galaxies on orbits that pass close to the
cluster core.
We also derive the most complete B-band Tully -Fisher relation
of inclined spiral galaxies in Fornax. A subcluster in the
South-West of the main cluster contributes considerably to the
scatter. The scatter for galaxies in the main cluster alone is
0.50 mag, which is slightly larger than the intrinsic scatter of
0.4 mag. We use the Tully -Fisher relation to derive a distance
modulus of Fornax relative to the Virgo cluster of
mag. The galaxies in the subcluster are
(
) mag brighter than the galaxies of the main cluster,
indicating that they are situated in the foreground. With their mean
velocity 95 km s-1 higher than that of the main cluster we
conclude that the subcluster is falling into the main Fornax cluster.
Key words: galaxies: clusters: general / galaxies: clusters: individual: Fornax / galaxies: fundamental parameters / galaxies: general / radio lines: galaxies
© ESO, 2001
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