论文标题
Seyfert Galaxies -ix中的化学丰度。氦丰度估计
Chemical abundances in Seyfert galaxies -IX. Helium abundance estimates
论文作者
论文摘要
首次依赖于电子温度直接测量的氢（HE/H）的氦气丰度是在狭窄的线区域（NLR）中得出的，该区域是从Seyfert 2核的局部样品中得出的。鉴于此，从Sloan Digital Sumpery Data Release Release 15和文献中考虑了来自Sloan Digital Sky Data Release Release 15的光学发射线强度[$ 3000 \：<λ\：<λ\：<λ\：<λ\：<λ\：<λ\：<λ\：<λ\：<λ\：<\：7000 $]。我们使用光电离模型网格来得出中性氦气的电离校正因子（ICF）。该ICF的应用表明，Seyfert 2的NLR与总氦气丰度相关的中性氦分数为$ \ sim $ 50％。我们发现Seyfert 2 Nuclei的氦气丰度范围从0.60到太阳值的0.60到2.50倍，而$ \ sim $ \ sim $ 85％的样品中当前的过 - 极丰度值。来自Seyfert 2的衍生（He/H） - （O/H）的丰度关系比星形区域（SFS）的衍生性关系是步进的，并且这种差异可能是由于狼雷特恒星的风中过多地注入了星际介质中的氦气。从回归到零金属性，通过使用Seyfert 2估计与SFS估计相结合，我们获得了原始的氦质量分数$ y _ _ {\ rm p} $ = 0.2441 $ \ pm $ 0.0037，这是一个很好的价值，从一个良好的一致性中推断出了从COSMIC MICROWAVES CORSMIC MICROWAVES CORSICTION IP的同意。 $ y _ {\ rm p} $ = 0.2471 $ \ pm $ 0.0003
For the first time, the helium abundance relative to hydrogen (He/H), which relied on direct measurements of the electron temperature, has been derived in the narrow line regions (NLRs) from a local sample of Seyfert 2 nuclei. In view of this, optical emission line intensities [$3000 \: < λ\: < \: 7000$] of 65 local Seyfert 2 nuclei ($z \: < \: 0.2$), taken from Sloan Digital Sky Survey Data Release 15 and additional compilation from the literature, were considered. We used photoionization model grid to derive an Ionization Correction Factor (ICF) for the neutral helium. The application of this ICF indicates that the NLRs of Seyfert 2 present a neutral helium fraction of $\sim$50 per cent in relation to the total helium abundance. We find that Seyfert 2 nuclei present helium abundance ranging from 0.60 to 2.50 times the solar value, while $\sim$85 per cent of the sample present over-solar abundance values. The derived (He/H)-(O/H) abundance relation from the Seyfert 2 is stepper than that of star-forming regions (SFs) and this difference could be due to excess of helium injected into the Interstellar Medium by the winds of Wolf Rayet stars. From a regression to zero metallicity, by using Seyfert 2 estimates combined with SFs estimates, we obtained a primordial helium mass fraction $Y_{\rm p}$=0.2441$\pm$0.0037, a value in good agreement with the one inferred from the temperature fluctuations of the cosmic microwave background by the Planck Collaboration, i.e. $Y_{\rm p}$=0.2471$\pm$0.0003
