论文标题
使用Broad MGII的极化，H $α$和H $β$线估算AGN中的超质量黑洞质量
Estimating supermassive black hole masses in AGNs using polarization of broad MgII, H$α$ and H$β$ lines
论文作者
论文摘要
对于1型活性银河核（AGN），赤道散射是主要的宽线极化机制，可以通过追踪跨极化平面位置的开普勒运动来测量超质量黑洞质量。到目前为止，该方法已用于30个对象，但仅用于H $α$排放线。我们通过首次将其应用于mg ii $λ$ 2798AA光谱线来探索这种方法，以在宽发射线中使用极化来确定SMBH质量。我们使用3D Monte Carlo辐射传输代码Stokes进行H $α$，H $β$和MG II系的赤道散射的同时建模。我们在MGII宽线区域（BLR）中包括了垂直流入和流出。我们发现，H $α$和H $β$线的极化状态几乎相同，而SMBH质量估计差7％。对于MG II线，我们发现极化角度$φ$具有恒定$φ$的额外“高原”，这比纯keplerian运动所期望的轮廓偏离。使用MG II线的SMBH质量估计高达35％，高于从H $α$和H $β$线获得的SMBH质量。我们的模型表明，对于BLR中的垂直流入和流出，与开普勒速度更高或可比性，可以将该方法作为获得SMBH质量的第一个近似值。
For type-1 active galactic nuclei (AGNs) for which the equatorial scattering is the dominant broad line polarization mechanism, it is possible to measure the supermassive black hole mass by tracing the Keplerian motion across the polarization plane positionangle. So far this method has been used for 30 objects but only for H$α$ emission line. We explore the possibilities this method for determining SMBH masses using polarization in broad emission lines by applying it for the first time to Mg II$λ$2798AA spectral line. We use 3D Monte Carlo radiative transfer code stokes for simultaneous modeling of equatorial scattering of H$α$, H$β$ and Mg II lines. We included vertical inflows and outflows in the MgII broad line region (BLR). We find that polarization states of H$α$ and H$β$ lines are almost identical and SMBH mass estimates differ by 7%. For Mg II line, we find that polarization angle $φ$ exhibits an additional "plateau" with a constant $φ$, which deviates than the profiles expected for pure Keplerian motion. SMBH mass estimates using Mg II line are higher by up to 35% than those obtained from H$α$ and H$β$ lines. Our model shows that for vertical inflows and outflows in the BLR that is higher or comparable to Keplerian velocity, this method can be applied as a first approximation for obtaining SMBH mass.
