Metallicity and age gradients in round elliptical galaxiesстатья
Статья опубликована в высокорейтинговом журнале
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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.
Аннотация:We probe stellar population age and metallicity distributions in nearby elliptical galaxies over the largest extension upto date. Long-slit spectroscopy is made by using the spectrograph SCORPIO of the 6-m telescope of the Special Astrophysical Observatory of the
Russian Academy of Sciencies. The Lick indices H-beta, Mgb, Fe5270, and Fe5335 are calculated along the slit upto radii of 1.3 to 3 r_e in 4 galaxies and upto 0.5 r_e in the fifth one. The comparison with evolutionary synthesis models of Simple Stellar Populations allows to disentangle age and metallicity and to measure both. We have found that the mean stellar age is constant along the radius only in one galaxy of 5. The other 4 galaxies demonstrate quite different behaviour of the mean stellar age: the outer parts are older than the centers in 3 cases and younger -- in one case. The metallicity gradients cannot be approximated by a single power law over the full radial extension in 4 galaxies of 5. The inner metallicity gradients within 0.5 r_e are all rather steep, steeper than -0.4 metallicity dex per radius dex, and are inconsistent with the origin of the elliptical galaxies by major merger.