| Téléchargement | - Voir la version finale : Evolution of the early-type galaxy fraction in clusters since z = 0.8 (PDF, 1.6 Mio)
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| DOI | Trouver le DOI : https://doi.org/10.1051/0004-6361/20078872 |
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| Auteur | Rechercher : Simard, L.1; Rechercher : Clowe, D.; Rechercher : Desai, V.; Rechercher : Dalcanton, J. J.; Rechercher : Von Der Linden, A.; Rechercher : Poggianti, B. M.; Rechercher : White, S. D. M.; Rechercher : Aragón-Salamanca, A.; Rechercher : De Lucia, G.; Rechercher : Halliday, C.; Rechercher : Jablonka, P.; Rechercher : Milvang-Jensen, B.; Rechercher : Saglia, R. P.; Rechercher : Pelló, R.; Rechercher : Rudnick, G. H.; Rechercher : Zaritsky, D. |
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| Affiliation | - Conseil national de recherches du Canada. Institut Herzberg d'astrophysique du CNRC
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| Format | Texte, Article |
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| Sujet | galaxies: fundamental parameters; galaxies: evolution; galaxies: clusters: general |
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| Résumé | We study the morphological content of a large sample of high-redshift clusters to determine its dependence on cluster mass and redshift. Quantitative morphologies are based on PSF-convolved, 2D bulge+disk decompositions of cluster and field galaxies on deep Very Large Telescope FORS2 images of eighteen, optically-selected galaxy clusters at observed as part of the ESO Distant Cluster Survey (“EDisCS”). Morphological content is characterized by the early-type galaxy fraction fet, and early-type galaxies are objectively selected based on their bulge fraction and image smoothness. This quantitative selection is equivalent to selecting galaxies visually classified as E or S0. Changes in early-type fractions as a function of cluster velocity dispersion, redshift and star-formation activity are studied. A set of 158 clusters extracted from the Sloan Digital Sky Survey is analyzed exactly as the distant EDisCS sample to provide a robust local comparison. We also compare our results to a set of clusters from the Millennium Simulation. Our main results are: (1) the early-type fractions of the SDSS and EDisCS clusters exhibit no clear trend as a function of cluster velocity dispersion. (2) Mid-z EDisCS clusters around σ = 500 km s-1 have fet 0.5 whereas high-z EDisCS clusters have fet 0.4. This represents a ~25% increase over a time interval of 2 Gyr. (3) There is a marked difference in the morphological content of EDisCS and SDSS clusters. None of the EDisCS clusters have early-type galaxy fractions greater than 0.6 whereas half of the SDSS clusters lie above this value. This difference is seen in clusters of all velocity dispersions. (4) There is a strong and clear correlation between morphology and star formation activity in SDSS and EDisCS clusters in the sense that decreasing fractions of [OII] emitters are tracked by increasing early-type fractions. This correlation holds independent of cluster velocity dispersion and redshift even though the fraction of [OII] emitters decreases from to in all environments. Our results pose an interesting challenge to structural transformation and star formation quenching processes that strongly depend on the global cluster environment (e.g., a dense ICM) and suggest that cluster membership may be of lesser importance than other variables in determining galaxy properties. |
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| Date de publication | 2009-10-15 |
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| Maison d’édition | EDP Sciences |
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| Dans | |
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| Langue | anglais |
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| Publications évaluées par des pairs | Oui |
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| Numéro NPARC | 23004828 |
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| Exporter la notice | Exporter en format RIS |
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| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
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| Identificateur de l’enregistrement | 590dc8dd-82a0-4e0b-bf00-c2b31bb67470 |
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| Enregistrement créé | 2019-01-03 |
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| Enregistrement modifié | 2020-05-30 |
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