论文标题
NGC 3227中宽线区域的动力学
The dynamics of the broad-line region in NGC 3227
论文作者
论文摘要
重新检查了用空间望远镜成像光谱仪（STIS）获得的NGC 3227的Seyfert 1核的档案哈勃太空望远镜（HST）观察结果，以限制广泛线区域（BLR）的可行光电离子模型。结果表明，BLR是一种部分电离，无尘的球形壳，由于其靠近超级质量的黑洞，因此在自由下落速度上崩溃，以人的自由速度崩溃。 BLR是在外部半径上界定的电离，与灰尘回响半径一致，并且随着中央UV-X射线源的接近，将变成Balmer Reverberation Radius内部的X射线发射等离子体。仅需要40 m_sun的氢来解释Balmer发射线的光度，但是通过重力压缩到测量5.5 x 10^24原子/cm^2的列中。假设辐射效率低下的积聚，X射线光度需要〜10^-2 m_sun/yr。但是，解释宽H-α发射线的光度所需的质量流入率为〜1 m_sun/yr。这两个估计之间的巨大差异表明，99％的流动气体必须重新定向到流出，并且在非常短的时间尺度上对应于约40年。或者，流入的辐射效率已被高估，或者X射线光度已被低估了。如果BLR确实是康普顿厚，则可能是明显的可能性。
Archival Hubble Space Telescope (HST) observations of the Seyfert 1 nucleus of NGC 3227 obtained with the Space Telescope Imaging Spectrograph (STIS) are re-examined in order to constrain a viable photoionization model for the broad-line region (BLR). The results imply that the BLR is a partially ionized, dust-free, spherical shell that is collapsing, supersonically, at the free-fall velocity due to its proximity to a supermassive black hole. The BLR is ionization bounded at the outer radius, coincident with the dust reverberation radius, and transforms into an X-ray emitting plasma inside the Balmer reverberation radius as the central UV--X-ray source is approached. Only 40 M_Sun of Hydrogen are required to explain the Balmer emission line luminosity, but it is compressed by gravity into a column measuring 5.5 x 10^24 atoms/cm^2. Assuming radiatively inefficient accretion, the X-ray luminosity requires ~ 10^-2 M_sun/yr. However, the mass inflow rate required to explain the luminosity of the broad H-alpha emission line is ~1 M_sun/yr. The very large disparity between these two estimates indicates that 99% of the inflowing gas must be re-directed into an outflow, and on a very short timescale corresponding to ~40 years. Alternatively, the radiative efficiency of the inflow has been overestimated, or the X-ray luminosity has been underestimated; a distinct possibility if the BLR is indeed Compton thick.
