Issue |
Astron. Astrophys. Suppl. Ser.
Volume 134, Number 1, January I 1999
|
|
---|---|---|
Page(s) | 75 - 86 | |
DOI | https://doi.org/10.1051/aas:1999434 | |
Published online | 15 January 1999 |
The central region of the Fornax cluster*
II. Spectroscopy and radial velocities of member and background galaxies
1
Sternwarte der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
2
Departamento de Astronomía y Astrofísica, P. Universidad Católica, Casilla 104, Santiago 22, Chile
3
UCO/Lick Observatory, University of California, Santa Cruz, CA 95064, U.S.A.
4
Feodor Lynen Fellow of the Alexander von Humboldt Foundation
Send offprint request to: M. Hilker
Received:
23
March
1998
Accepted:
7
July
1998
Radial velocities of 94 galaxies brighter than about mag
in the direction of the central Fornax cluster have been measured.
Except for 8 Fornax members, all galaxies lie in
the background. Among the 8 members, there are 5 nucleated dwarf ellipticals
that are already listed in the FCC (Ferguson 1989). Two
of the 3 "new”
members are very compact and have surface brightnesses comparable to globular
clusters, however their luminosities are in the range of dwarf elliptical
nuclei.
The measured line indices (especially Mg2, Hβ, and iron) of the brighter
of the compact objects suggest a solar metallicity, whereas
the fainter compact object as well as the dE, Ns have line
indices that are similar to those of old metal-poor globular clusters (GCs).
However, with these data it is not possible to clearly classify the
compact objects either as very bright globular clusters, isolated nuclei of
dE, Ns, or even compact ellipticals.
A background galaxy
cluster at
has been found just behind the center of the Fornax
cluster. This explains the excess population of galaxies reported in
Paper I. The brightest galaxy of the background cluster lies only
south of NGC 1399 and is comparable in absolute
luminosity with the central Fornax galaxy itself.
Key words: galaxies: clusters: Fornax cluster / galaxies: distances and redshifts / galaxies: abundances / galaxies: dwarf
© European Southern Observatory (ESO), 1999