Issue |
A&A
Volume 488, Number 3, September IV 2008
|
|
---|---|---|
Page(s) | 853 - 860 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:200809531 | |
Published online | 17 July 2008 |
Star formation histories of early-type galaxies at z = 1.2 in cluster and field environments
1
European Southern Observatory, Karl Schwarzschild Strasse 2, Garching bei Muenchen 85748, Germany
2
National Radio Astronomy Observatory, PO Box O, Socorro, NM 87801, USA
3
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
4
INAF-Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34131 Trieste, Italy
Received:
7
February
2008
Accepted:
23
June
2008
We derive the star formation histories of early-type galaxies at in
both low and high density environments. To this purpose, we compare the co-added
spectroscopic and 8–9 band photometric
data of 43 mass selected early-type galaxies in the massive cluster RDCS J1252.9-2927
and the GOODS/CDF-S field with a large grid of composite stellar population models
based on the Bruzual & Charlot templates.
We find that the cluster early-type galaxies formed the bulk of their stars
approximately 0.5 Gyr earlier than early-types in the field, whereas field early-types
presumably finish forming their stellar content on a longer time scale. Such
a difference is particularly evident at masses
, whereas it
becomes negligible for the most massive galaxies. While our differential analysis of the
stellar population parameters of
cluster and field galaxies in the same mass range convincingly shows distinct star
formation histories, the absolute age difference remains model dependent. Using the
star formation histories that best fit the SEDs of the red sequence galaxies in
RDCS 1252.9-2927, we reconstruct the evolution of the cluster red sequence and find
that it was established over 1 Gyr and is expected to dissolve by
.
Key words: galaxies: clusters: individual: RDCS 1252.9-2927 / galaxies: evolution / galaxies: elliptical and lenticular, cD
© ESO, 2008
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