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Stellar population constraints on the dark matter content and origin of ultra-compact dwarf galaxiesстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
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., Bergond G.
- Журнал: Monthly Notices of the Royal Astronomical Society
- Том: 390
- Год издания: 2008
- Издательство: Oxford Journals, Oxford University Press
- Местоположение издательства: Oxford, UK, England
- Первая страница: 906
- Последняя страница: 912
- DOI: 10.1111/j.1365-2966.2008.13845.x
- Аннотация: We analyse intermediate-resolution Very Large Telescope (VLT) FLAMES/Giraffe spectra of six ultra-compact dwarf (UCD) galaxies in the Fornax cluster. We obtained velocity dispersions and stellar population properties by full spectral fitting against PEGASE.HR models. Objects span a large range of metallicities (-0.95 to -0.23 dex), four of them are older than 8 Gyr. Comparison of the stellar and dynamical masses suggests that UCDs have little dark matter at best. For one object, UCD3, the Salpeter initial mass function (IMF) results in the stellar mass significantly exceeding the dynamical one, whereas for the Kroupa IMF the values coincide. Although, this object may have peculiar dynamics or/and stellar populations, the Kroupa IMF seems more realistic. We find that UCDs lie well above the metallicity-luminosity relation of early-type galaxies. The same behaviour is demonstrated by some of the massive Milky Way globular clusters, known to contain composite stellar populations. Our results support the two following UCD formation scenario: (i) tidal stripping of nucleated dwarf elliptical galaxies and (ii) formation of tidal superclusters in galaxy mergers. We also discuss some of the alternative channels of the UCD formation binding them to globular clusters. Based on the archival ESO VLT data (programmes 074.A-0756 and 074.A-0508) available through http://archive.eso.org/.
- Добавил в систему: Чилингарян Игорь Владимирович