| Issue |
A&A
Volume 429, Number 1, January I 2005
|
|
|---|---|---|
| Page(s) | 101 - 114 | |
| Section | Cosmology (including clusters of galaxies) | |
| DOI | https://doi.org/10.1051/0004-6361:20041215 | |
| Published online | 13 December 2004 | |
The intermediate-redshift galaxy cluster CL 0048-2942*
Stellar populations
1
Centro de Astronomia e Astrofísica da Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal e-mail: serote@oal.ul.pt
2
Depto. de Matemática Aplicada, Faculdade de Ciências, Univ. do Porto, R. do Campo Alegre 687, 4169-007 Porto, Portugal
3
Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: lobo@astro.up.pt
4
Institut d'Astrophysique de Paris, 98bis Bd. Arago, 75014 Paris, France e-mail: durret@iap.fr
5
Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy e-mail: iovino@brera.mi.astro.it
6
Instituto de Astrofísica de Andalucía (CSIC), Camino Bajo de Huétor, 24, 18008 Granada, Spain e-mail: isabel@iaa.es
Received:
3
May
2004
Accepted:
28
August
2004
We present a detailed study of the cluster CL 0048-2942,
located at 
, based on a photometric and spectroscopic
catalogue of 54 galaxies in a 
arcmin2 region centred
in that cluster. Of these, 23 galaxies were found to belong to the
cluster. Based on this sample,
the line-of-sight velocity dispersion of the cluster is approximately 
km s-1.
We have performed stellar population synthesis in the
cluster members as well as in the field galaxies of the sample and
found that there are population gradients in the cluster with central
galaxies hosting mainly intermediate/old populations whereas galaxies
in the cluster outskirts show clearly an increase of younger
populations, meaning that star formation is predominantly taking place
in the outer regions of the cluster. In a general way, field galaxies
seem to host less evolved stellar populations than cluster members.
In fact, in terms of ages, young supergiant stars dominate the spectra
of field galaxies whereas cluster galaxies display a dominant number
of old and intermediate age stars. Following the work of other
authors (e.g. Dressler et al. [CITE]) we have estimated the percentage
of K+A galaxies in our sample and found around
13% in the cluster and 10% in the field. These values were estimated
through means of a new method, based on stellar population synthesis results,
that takes into account all possible absorption features in the spectrum
and thus makes optimal use of the data.
Key words: galaxies: clusters: individual: CL 0048-2942 / galaxies: clusters: general / galaxies: distances and redshifts / galaxies: stellar content
© ESO, 2005
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