Ages and abundances in the large-scale stellar discs of the nearby S0 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: 19 июля 2013 г.
Аннотация:By undertaking deep long-slit spectroscopy with the focal reducer SCORPIO of
the Russian 6m telescope, we studied stellar population properties
and their variation with radius in 15 nearby S0 galaxies sampling a wide
range of luminosities and environments. For the large-scale stellar disks
of S0s, we have measured SSP-equivalent metallicities ranging from the
solar one down to [Z/H]=-0.4 - -0.7, rather high magnesium-to-iron ratios,
[Mg/Fe] > +0.2, and mostly old SSP-equivalent ages.
Nine of 15 (60%) galaxies have large-scale stellar disks older
than 10 Gyr, and among those we find all the galaxies which reside in
denser environments. The isolated galaxies may have intermediate-age
stellar disks which are 7-9 Gyr old. Only two galaxies of our sample,
NGC 4111 and NGC 7332, reveal SSP-equivalent ages of their disks of
2-3 Gyrs. Just these two young disks appear to be thin, while the other,
older disks have scale heights typical for thick stellar disks. The
stellar populations in the bulges at radii of 0.5r_eff are on
the contrary more metal-rich than the solar metallicity,
with the ages homogeneously distributed between 2 and 15 Gyr, being
almost always younger than the disks. We conclude that
S0 galaxies could not form in groups at z=0.4 as is thought now; a
new scenario of the general evolution of disk galaxies is proposed
instead.