The S2N2 metallicity calibrator and the abundance gradient of M 33
The S2N2 metallicity calibrator and the abundance gradient of M 33
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S2N2 金属丰度校准器和 M 33 的丰度梯度
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
R. Corradi
中科院分区：
文献类型：
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作者：
K. Viironen;G. Delgado;A. Mampaso;Laura Magrini;R. Corradi
我们引入log（Hα/[S II]λλ6717+6731）与log（Hα/[N II]λ6583）（S2 N2）诊断图作为外星系H II区的金属丰度和电离参数指标。从实验和理论两方面研究了H Ⅱ区在S_2N_2图中的位置。我们发现，对于广泛的金属丰度，S2 N2图在金属丰度-电离参数平面上给出了单值结果。我们证明了S2 N2图是估算高红移（z <$2）H II星系金属丰度的有力工具。最后，我们从S2 N2图中得到了M33中76个H II区域的金属丰度，并计算出该星系的O/H丰度梯度为−0.05（±0.01）dex kpc −1。
We introduce the log(Hα/[S II]λλ6717+6731) versus log(Hα/[N II]λ6583) (S2N2) diagnostic diagram as a metallicity and ionization parameter indicator for H II regions in external galaxies. The location of H II regions in the S2N2 diagram was studied both empirically and theoretically. We found that, for a wide range of metallicities, the S2N2 diagram gives single-valued results in the metallicity‐ionization parameter plane. We demonstrate that the S2N2 diagram is a powerful tool to estimate metallicities of high-redshift (z ∼ 2) H II galaxies. Finally, we derive the metallicity for 76 H II regions in M 33 from the S2N2 diagram and calculate an O/H abundance gradient for this galaxy of −0.05 (±0.01) dex kpc −1 .