论文标题
用于估计HII区域N/O比率的新校准
New calibrations for estimating the N/O ratio in HII regions
论文作者
论文摘要
We use a sample of 536 \hii\ regions located in nearby spirals, with an homogeneous determination of their $T_e$-based abundances, to obtain new empirical calibrations of the N2O2, N2S2, O3N2, and N2 strong-line indices to estimate the nitrogen-to-oxygen abundance ratio when auroral lines are not detected.所有索引与我们的\ hii \区域样本的基于$ t_e $的$ \ log $（n/o）密切相关，甚至比$ 12+\ log $（o/h）更强烈。 N2O2是最密切相关的索引，与$ \ log $（n/o）-N2O2关系的最佳拟合是通过二阶多项式获得的。派生的关系具有低色散（{\ em rms} $ <$ 0.09〜DEX），在$ -1.74 <$ N2O2 $ <0.62 $（或$ -1.81 <$ $ \ $ \ log $（n/o）$ <-0.13 $）的范围内有效。我们已经将校准与以前的校准进行了比较，并讨论了它们之间的差异，以用作校准器的对象的性质。
We use a sample of 536 \hii\ regions located in nearby spirals, with an homogeneous determination of their $T_e$-based abundances, to obtain new empirical calibrations of the N2O2, N2S2, O3N2, and N2 strong-line indices to estimate the nitrogen-to-oxygen abundance ratio when auroral lines are not detected. All indices are strongly correlated with the $T_e$-based $\log$(N/O) for our \hii\ region sample, even more strongly than with $12+\log$(O/H). N2O2 is the most strongly correlated index, and the best fit to the $\log$(N/O)-N2O2 relation is obtained with a second-order polynomial. The derived relation has a low dispersion ({\em rms}$<$0.09~dex), being valid in the range $-1.74 < $ N2O2 $< 0.62$ (or $-1.81 < $ $\log$(N/O) $< -0.13$). We have compared our calibration with previous ones and have discussed the differences between them in terms of the nature of the objects used as calibrators.
