The Oxygen Abundance Calibrations and N/O Abundance Ratios of ~40,000 SDSS Star-forming Galaxies
The Oxygen Abundance Calibrations and N/O Abundance Ratios of ~40,000 SDSS Star-forming Galaxies
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DOI：
10.1086/507592
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发表时间：
2006-07
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影响因子：
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通讯作者：
Y. Liang;S. Yin;F. Hammer;L. Deng;H. Flores;B. Z. Naoc;C. Gepi;O. Paris-meudon;F. D. O. Physics;H. University;China
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文献类型：
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作者：
Y. Liang;S. Yin;F. Hammer;L. Deng;H. Flores;B. Z. Naoc;C. Gepi;O. Paris-meudon;F. D. O. Physics;H. University;China
利用SDSSDR2选取的38,478个恒星形成星系的大样本，我们从几个金属丰度敏感的发射线比[N II]/Hα，[O III]/[N II]，[N II]/[O II]，[N II]/[S II]，[S II]/Hα和[O III]/Hβ得到了氧丰度的解析定标。这套一致的强线氧丰度定标将对未来的丰度研究有用。在这些定标中，[N II]/[O II]对于富金属星系来说是最好的，因为它不依赖于电离参数，而且散射很小。首先必须适当地考虑尘埃消退。这些定标更适合于富金属星系[8.4<；12+log(O/H)<；9.3]和星系的核区。所观察到的关系与Kewley&多普塔的光致电离模型所预期的一致。然而，大多数观测数据分布在电离参数Q从1×107到8×107厘米S-1的范围内，对应的对数U=-3.5到-2.5，比模型所建议的要窄。我们还估计了这一大样本星系的(N/O)丰度比，这与氮的“主要”和主要的“次要”成分的组合是一致的。
Using a large sample of 38,478 star-forming galaxies selected from SDSS DR2, we derive analytical calibrations for oxygen abundances from several metallicity-sensitive emission-line ratios: [N II]/Hα, [O III]/[N II], [N II]/[O II], [N II]/[S II], [S II]/Hα, and [O III]/Hβ. This consistent set of strong-line oxygen abundance calibrations will be useful for future abundance studies. Among these calibrations, [N II]/[O II] is the best for metal-rich galaxies due to its independence on ionization parameter and low scatter. Dust extinction must be considered properly at first. These calibrations are more suitable for metal-rich galaxies [8.4 < 12 + log(O/H) < 9.3] and for the nuclear regions of galaxies. The observed relations are consistent with those expected from the photoionization models of Kewley & Dopita. However, most of the observational data spread in a range of ionization parameter q from 1 × 107 to 8 × 107 cm s-1, corresponding to log U = -3.5 to -2.5, narrower than that suggested by the models. We also estimate the (N/O) abundance ratios of this large sample of galaxies, and these are consistent with the combination of a "primary" and a dominant "secondary" component of nitrogen.