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Kinematics and stellar populations of low-luminosity early-type galaxies in the Abell 496 clusterстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Chilingarian I.V., Cayatte V., Durret F., Adami C., Balkowski C., Chemin L., Laganá T.F., Prugniel P.
- Журнал: Astronomy and Astrophysics
- Том: 486
- Год издания: 2008
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- Первая страница: 85
- Последняя страница: 97
- DOI: 10.1051/0004-6361:20078709
- Аннотация: Context: The morphology and stellar populations of low-luminosity early-type galaxies in clusters have until now been limited to a few relatively nearby clusters such as Virgo or Fornax. Scenarii for the formation and evolution of dwarf galaxies in clusters are therefore not well constrained. Aims: We investigate here the morphology and stellar populations of low-luminosity galaxies in the relaxed richness class 1 cluster Abell 496 (z = 0.0330). Methods: Deep multiband imaging obtained with the CFHT Megacam allowed us to select a sample of faint galaxies, defined here as objects with magnitudes 18 < r' < 22 mag within a 1.2 arcsec fibre (-18.8 < MB < -15.1 mag). We observed 118 galaxies spectroscopically with the ESO VLT FLAMES/Giraffe spectrograph with a resolving power R = 6300. We present structural analysis and colour maps for the 48 galaxies belonging to the cluster. We fit the spectra of 46 objects with PEGASE.HR synthetic spectra to estimate the ages, metallicities, and velocity dispersions. We estimated possible biases by similarly analysing spectra of ~1200 early-type galaxies from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6). We computed values of α/Fe abundance ratios from the measurements of Lick indices. We briefly discuss effects of the fixed aperture size on the measurements. Results: For the first time, high-precision estimates of stellar population properties have been obtained for a large sample of faint galaxies in a cluster, allowing for the extension of relations between stellar populations and internal kinematics to the low-velocity dispersion regime. We have revealed a peculiar population of elliptical galaxies in the core of the cluster, resembling massive early-type galaxies by their stellar population properties and velocity dispersions, but having luminosities of about 2 mag fainter. Conclusions: External mechanisms of gas removal (ram pressure stripping and gravitational harassment) are more likely to have occurred than internal mechanisms such as supernova-driven winds. The violent tidal stripping of intermediate-luminosity, early-type galaxies in the cluster core can explain the properties of the peculiar elliptical galaxies surrounding the cD galaxy. Based on observations obtained with ESO VLT (program 074.A-0533) and MegaPrime/MegaCam, a joint project of Canada France Hawaii Telescope (CFHT) and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (program 03BF12), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. All the spectral and imaging data used in this paper are available through the VO-Paris Data Centre: http://voplus.obspm.fr/DataCollections/Abell0496/
- Добавил в систему: Чилингарян Игорь Владимирович