For the first time, neon abundance has been derived in the narrow line region from a sample of Seyfert 2 nuclei. In view of this, we compiled from the literature fluxes of optical and infrared (IR) narrow emission lines for 35 Seyfert 2 nuclei in the local universe ($z \:\lesssim \:0.06$). The relative intensities of emission lines were used to derive the ionic and total neon and oxygen abundances through electron temperature estimations (Te-method). For the neon, abundance estimates were obtained by using both Te-method and IR-method. Based on photoionization model results, we found a lower electron temperature [$t_{\rm e}({\rm Ne\, \small {III}})$] for the gas phase where the Ne2 + is located in comparison with t3 for the O2 + ion. We find that the differences (D) between Ne2 +/H+ ionic abundances calculated from IR-method and Te-method (assuming t3 in the Ne2 +/H+ derivation) are similar to the derivations in star-forming regions (SFs) and they are reduced by a mean factor of ∼3 when $t_{\rm e}({\rm Ne\, \small {III}})$ is considered. We propose a semi-empirical Ionization Correction Factor (ICF) for the neon, based on [Ne ii]12.81$\rm{\mu m}$, [Ne iii]15.56$\rm{\mu m}$, and oxygen ionic abundance ratios. We find that the average Ne/H abundance for the Seyfert 2s sample is nearly 2 times higher than similar estimate for SFs. Finally, for the very high metallicity regime (i.e. [$\rm 12+log(O/H)\: \gtrsim \: 8.80$]) an increase in Ne/O with O/H is found, which likely indicates secondary stellar production for the neon.

中文翻译：

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Seyfert 星系中的化学丰度 - VII。基于光学和红外发射线的氖的直接丰度测定

首次从 Seyfert 2 原子核样本中推导出窄线区域的氖丰度。鉴于此，我们从文献中汇编了局部宇宙中 35 个 Seyfert 2 核的光学和红外 (IR) 窄发射线通量 ($z \:\lesssim \:0.06$)。发射线的相对强度用于通过电子温度估计（Te 方法）得出离子和总氖和氧丰度。对于氖，丰度估计是通过使用 Te 方法和 IR 方法获得的。基于光电离模型结果，我们发现与 t3 相比，Ne2 + 所在气相的电子温度 [$t_{\rm e}({\rm Ne\, \small {III}})$]对于 O2 + 离子。我们发现从 IR 方法和 Te 方法计算的 Ne2 +/H+ 离子丰度之间的差异（D）（假设 Ne2 +/H+ 推导中的 t3）与恒星形成区域（SFs）中的推导相似，它们当考虑 $t_{\rm e}({\rm Ne\, \small {III}})$ 时，平均因子减少了 ∼3。我们提出了基于 [Ne ii]12.81$\rm{\mu m}$、[Ne iii]15.56$\rm{\mu m}$ 和氧气的氖的半经验电离校正因子 (ICF)离子丰度比。我们发现 Seyfert 2s 样本的平均 Ne/H 丰度比 SFs 的类似估计值高近 2 倍。最后，对于非常高的金属丰度状态（即 [$\rm 12+log(O/H)\: \gtrsim \: 8.80$]），发现 Ne/O 随 O/H 增加，这可能表明次级恒星霓虹灯的生产。