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arXiv 1004.3683astro-ph.CO
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来自SDSS - II的低表面亮度盘状星系的大样本。表面亮度箱中的金属丰度

A large sample of low surface brightness disc galaxies from the SDSS- II. Metallicities in surface brightness bins

Y. C. Liang, G. H. Zhong, F. Hammer, X. Y. Chen, F. S. Liu, D. Gao, J. Y. Hu, L. C. Deng, B. Zhang

摘要:

我们研究了从Sloan数字巡天数据发布4(SDSS-DR 4)主星系样本中选取的一个B波段中心表面亮度μ 0(B)>22 mag arcsec^(-2)的大样本低表面亮度星系(LSBG)的光谱特性。同时还选取了一个大样本的盘主导高表面亮度星系(HSBG,μ 0(B)<22 mag arcsec^(-2))进行比较。为了更详细地研究它们,这些样本星系根据μ 0(B)(单位为磁角秒^(-2))进一步分为四个亚组:vLSBG(24.5-22.75)、iLSBG(22.75-22.0)、iHSBG(22.0-21.25)和vHSBG(<21.25)。光谱发射线比诊断图显示,四个亚群的活动星系核分数都很小(<9%)。选取了21,032个光谱观测质量较好的恒星形成星系,进一步研究了它们的尘埃消光、强线比、金属丰度和恒星质量-金属丰度关系。vLSBG具有较低的消光值,并且比其他子群具有较少的金属丰富和大质量星系。我们的LSBG的氧丰度不像文献中研究的LSBG中的HII区域的氧丰度那么低,这可能是因为我们的样品更发光,并且因为使用了不同的金属丰度校准。我们发现vLSBG、iLSBG和iHSBG的12+log(O/H)和mu 0(B)之间存在相关性,但这可能是mu 0(B)和恒星质量之间的相关性以及众所周知的质量-金属丰度关系的结果。这一大样本表明LSBG的金属丰度和恒星质量跨越了很宽的范围,并且它们与正常星系的恒星质量-金属丰度关系和N/O-O/H关系接近。这表明LSBG和HSBG没有显著不同的恒星形成和化学富集历史。

英文摘要:

We study the spectroscopic properties of a large sample of Low Surface Brightness galaxies (LSBGs) (with B-band central surface brightness mu0(B)>22 mag arcsec^(-2)) selected from the Sloan Digital Sky Survey Data Release 4 (SDSS-DR4) main galaxy sample. A large sample of disk-dominated High Surface Brightness galaxies (HSBGs, with mu0(B)<22 mag arcsec^(-2)) are also selected for comparison simultaneously. To study them in more details, these sample galaxies are further divided into four subgroups according to mu0(B) (in units of mag arcsec^(-2)): vLSBGs (24.5-22.75),iLSBGs (22.75-22.0), iHSBGs (22.0-21.25), and vHSBGs (<21.25). The diagnostic diagram from spectral emission-line ratios shows that the AGN fractions of all the four subgroups are small (<9%). The 21,032 star-forming galaxies with good quality spectroscopic observations are further selected for studying their dust extinction, strong-line ratios, metallicities and stellar mass-metallicities relations. The vLSBGs have lower extinction values and have less metal-rich and massive galaxies than the other subgroups. The oxygen abundances of our LSBGs are not as low as those of the HII regions in LSBGs studied in literature, which could be because our samples are more luminous, and because of the different metallicity calibrations used. We find a correlation between 12+log(O/H) and mu0(B) for vLSBGs, iLSBGs and iHSBGs but show that this could be a result of correlation between mu0(B) and stellar mass and the well-known mass-metallicity relation. This large sample shows that LSBGs span a wide range in metallicity and stellar mass, and they lie nearly on the stellar mass vs. metallicity and N/O vs. O/H relations of normal galaxies. This suggests that LSBGs and HSBGs have not had dramatically different star formation and chemical enrichment histories.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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