标题： 活动星系核中利用氢帕申线的新黑洞质量估计方法 显示英文标题

标题： New Estimators of Black Hole Mass in Active Galactic Nuclei with Hydrogen Paschen Lines

摘要： 超过50%的活动星系核（AGNs）被认为呈红色并且受到尘埃遮蔽的影响。 同时，流行的AGNs光谱诊断方法基于光学或紫外线光，使得尘埃遮蔽成为理解AGNs总体性质以及其中超大质量黑洞的主要关注点。 为了提供一种研究尘埃AGNs特性的方法，我们基于近红外（NIR）氢发射线（如P$\alpha$和P$\beta$）的速度宽度和光度推导出新的黑洞（BH）质量估计器，并且还研究了这些氢线的线比。 为了推导黑洞质量（$M_{\rm BH}$）估计器，我们使用了一个包含37个未被遮蔽的I型AGNs的样本，其$M_{\rm BH}$范围为$10^{6.8}$-$10^{9.4} M_{\odot}$，其中$M_{\rm BH}$来自于使用巴尔末线的延时映射方法或单次观测测量方法。 我们的工作表明，$M_{\rm BH}$可以从帕申线光度和速度宽度估计到0.18 - 0.24 dex（均方根散射）的精度。 我们还表明，帕申线和巴尔末线的平均线比率是$\mathrm{\frac{H\alpha}{P\alpha}} \simeq 9.00$，$\mathrm{\frac{H\beta}{P\alpha}} \simeq 2.70$，这与典型的活动星系核宽线区环境下的Case B复合是一致的。 这些比率在估计红色活动星系核宽线区（BLR）的尘埃消光量时可以作为参考点。 我们期望未来将新的黑洞质量估算方法应用于红色、有尘埃的活动星系核，能够为被遮挡的活动星系核提供新的视角。 显示英文摘要

摘要： More than 50% of Active Galactic Nuclei (AGNs) are suspected to be red and affected by dust-obscuration. Meanwhile, popular spectral diagnostics of AGNs are based on optical or ultraviolet light, making the dust obscuration as a primary concern for understanding the general nature of AGNs and supermassive black holes residing in them. To provide with a method of investigating properties of the dusty AGNs, we derive new black hole (BH) mass estimators based on velocity widths and luminosities of Near Infrared (NIR) hydrogen emission lines such as P$\alpha$ and P$\beta$, and also investigate the line ratios of these Hydrogen lines. To derive the BH mass ($M_{\rm BH}$) estimators, we used a sample of 37 unobscured Type-1 AGNs with a $M_{\rm BH}$ range of $10^{6.8}$-$10^{9.4} M_{\odot}$, where $M_{\rm BH}$ come from either reverberation mapping method or single-epoch measurement method using Balmer lines. Our work shows that $M_{\rm BH}$ can be estimated from the Paschen line luminosities and the velocity widths to the accuracy of 0.18 - 0.24 dex (rms scatter). We also show that the mean line ratios of the Paschen lines and the Balmer lines are $\mathrm{\frac{H\alpha}{P\alpha}} \simeq 9.00$, $\mathrm{\frac{H\beta}{P\alpha}} \simeq 2.70$, which are consistent with a Case B recombination under a typical AGN broad line region environment. These ratios can be used as reference points when estimating the amount of dust extinction over the broad line region (BLR) for red AGNs. We expect the future application of the new BH mass estimators on red, dusty AGNs to provide a fresh view of obscured AGNs.