期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 423, 期 1, 页码 962-982出版社
OXFORD UNIV PRESS
DOI: 10.1111/j.1365-2966.2012.20938.x
关键词
galaxies: abundances; galaxies: bulges; galaxies: evolution; galaxies: formation; galaxies: kinematics and dynamics; galaxies: stellar content
资金
- La Silla Paranal Observatory [76.B-0375, 80.B-00754]
- Padua University [CPDA089220/08, 60A02-5934/09, 60A02-1283/10, CPS0204, CPDR095001/09, CPDR115539/11]
- Italian Space Agency [ASI-INAF I/009/10/0]
- Spanish MICINN [CSD2006-00070, AYA2007-67965-C03-01, AYA2010-21887-C04-04]
- European Community [229517]
We present the radial profiles of the H beta, Mg and Fe line-strength indices for a sample of eight spiral galaxies with a low-surface-brightness stellar disc and a bulge. The correlations between the central values of the line-strength indices and velocity dispersion are consistent with those known for early-type galaxies and bulges of high-surface-brightness galaxies. The age, metallicity and a/Fe enhancement of the stellar populations in the bulge-dominated region are obtained using stellar population models with variable element abundance ratios. Almost all the sample bulges are characterized by a young stellar population, ongoing star formation and a solar a/Fe enhancement. Their metallicity spans from high to subsolar values. No significant gradient in age and a/Fe enhancement is measured, whereas a negative metallicity gradient is found only in a few cases. These properties suggest that a pure dissipative collapse cannot explain the formation of all the sample bulges and that other phenomena, such as mergers or acquisition events, need to be invoked. Such a picture is also supported by the lack of a correlation between the central value and the gradient of the metallicity in bulges with very low metallicity. The stellar populations of the bulges hosted by low-surface-brightness discs share many properties with those of high-surface-brightness galaxies. Therefore, they are likely to have common formation scenarios and evolution histories. A strong interplay between bulges and discs is ruled out by the fact that, in spite of being hosted by discs with extremely different properties, the bulges of low- and high-surface-brightness discs are remarkably similar.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据