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Old stellar disks and the origin of S0 galaxiesстатья
Информация о цитировании статьи получена из
Scopus
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
- Автор: Sil’chenko O.
- Журнал: Memorie della Societa Astronomica Italiana Supplementi
- Том: 25
- Год издания: 2013
- Первая страница: 93
- Последняя страница: 96
- Аннотация: We studied stellar population properties and their variations along the radius in 21 nearby S0 galaxies. By calculating Lick indices H-beta, Mgb, Fe5270, and Fe5335, we have estimated SSP-equivalent ages, metallicities, and magnesium-to-iron ratios in their large-scale stellar disks. We have found mostly magnesium overabundant stellar populations in the disks, [Mg/Fe]>+0.2, and in 14 of 21 the mean stellar ages are larger than 11 Gyr. The large ages and magnesium-to-iron overabundance of the outer disks of nearby S0s contradict the commonly accepted scenario of S0 galaxy formation from spirals by quenching their star formation during infall into dense environments at intermediate redshifts, z=0.4-0.5 (4-5 Gyr ago). We propose a new scenario according to which S0 galaxies as a class are a primordial type of disk galaxies forming at z>2 from highly-turbulent gaseous clumpy disks. Many of them become later spirals by accreting external high-momentum cold gas, smoothly inflowing on the prolonged timescales and giving a rise to thin disks. In dense environments cold gas accretion is difficult to retain, so the majority of primordial S0s in clusters and rich groups have remained S0s becoming the dominant galaxy population there at z=0.
- Добавил в систему: Сильченко Ольга Касьяновна