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arXiv 1309.7873astro-ph.CO
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模拟光度混响数据--3C 120的盘状宽线区和潜在的更大黑洞质量

Modelling photometric reverberation data -- a disk-like broad-line region and a potentially larger black hole mass for 3C120

F. Pozo Nuñez, M. Haas, M. Ramolla, C. Bruckmann, C. Westhues, R. Chini, K. Steenbrugge, R. Lemke, M. Murphy, W. Kollatschny

摘要:

我们认为光度混响映射,其中的核连续变化监测通过一个宽带滤波器和发射线云的宽线区域(BLR)的回波测量与合适的窄带(NB)过滤器。我们调查如何不完整的发射线覆盖的NB过滤器影响的BLR大小的确定。这包括两种基本情况:1)线翼的蓝色和红色部分的对称切割,以及2)滤光器相对于线中心不对称地定位,使得基本上完整的一半发射线包含在NB滤光器中。假设BLR的大小主要是由圆形开普勒轨道,我们发现,线翼的对称切割可能会导致高估的BLR大小小于5%。不对称的半线覆盖的情况下,类似于我们的数据的塞弗特1星系3C 120,产生的BLR大小的偏差小于1%。我们的研究结果表明,任何BLR大小的偏见,由于窄带线切割光度混响映射是小的,在大多数情况下可以忽略不计。我们使用良好采样的光度混响映射光变曲线,在连续谱和Hbeta光变曲线中具有急剧变化的特征,以确定3C 120的Hbeta BLR的几何类型。光变曲线的建模,假设BLR基本上是维里化的,反对球形几何形状,而倾向于一个接近面的盘状几何形状,倾角i = 10 +/- 4度,从22到28光日。低倾角可能导致一个更大的黑洞质量比使用平均几何比例因子f=5.5时导出。本文讨论了Seyfert 1星系偏离M_BH -σ关系的情况.

英文摘要:

We consider photometric reverberation mapping, where the nuclear continuum variations are monitored via a broad-band filter and the echo of emission line clouds of the broad line region (BLR) is measured with a suitable narrow-band (NB) filter. We investigate how an incomplete emission-line coverage by the NB filter influences the BLR size determination. This includes two basic cases: 1) a symmetric cut of the blue and red part of the line wings, and 2) the filter positioned asymmetrically to the line centre so that essentially a complete half of the emission line is contained in the NB filter. Under the assumption that the BLR size is dominated by circular Keplerian orbits, we find that symmetric cutting of line wings may lead to overestimating the BLR size by less than 5%. The case of asymmetric half-line coverage, similar as for our data of the Seyfert 1 galaxy 3C120, yields the BLR size with a bias of less than 1%. Our results suggest that any BLR size bias due to narrow-band line cut in photometric reverberation mapping is small and in most cases negligible. We used well sampled photometric reverberation mapping light curves with sharp variation features in both the continuum and the Hbeta light curves to determine the geometry type of the Hbeta BLR for 3C120. Modelling of the light curve, under the assumption that the BLR is essentially virialised, argues against a spherical geometry and favours a nearly face-on disk-like geometry with inclination i = 10 +/- 4 deg and extension from 22 to 28 light days. The low inclination may lead to a larger black hole mass than the derived when using the average geometry scaling factor f=5.5. We discuss deviations of Seyfert 1 galaxies from the M_BH - sigma relation.

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