Volume 488, Number 3, September IV 2008
|Page(s)||853 - 860|
|Section||Cosmology (including clusters of galaxies)|
|Published online||17 July 2008|
Star formation histories of early-type galaxies at z = 1.2 in cluster and field environments
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
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
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.