The Emission-Line Properties of Low-Redshift Quasi-stellar Objects. II. The Relation to Radio Type
The Emission-Line Properties of Low-Redshift Quasi-stellar Objects. II. The Relation to Radio Type
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DOI：
10.1086/313058
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发表时间：
1997-12
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影响因子：
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通讯作者：
M. Corbin
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文献类型：
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作者：
M. Corbin
本文报道了45个类星体在红移0.045-0.592范围内的光学分光光度测量结果。这些数据与Boroson和绿色获得的87个低红移类星体和类星体的光谱样本相结合，更广泛地研究了Hβ，[O III] λ5007和Fe II光学谱线的性质与天体的射电、光学和X射线连续谱参数的关系。我们推导了类星体的一个完整的相关矩阵，并对平坦射电谱（FRS）类星体、陡射电谱（SRS）类星体和射电宁静天体（QSO）的子样本进行了双样本检验。主要研究结果如下：1.我们确认Hβ轮廓在四分之一最大值和半最大值点的宽度与6 cm射电核心通量与5500 nm处光学连续谱测量的通量之比成反比，这被认为是在波束模型下物体射电轴方向的指示器。Hβ轮廓宽度与任何线或连续谱参数都没有很强的相关性，这些参数可能是中央引擎内在动力的指标，包括扩展的射电光度。相关矩阵的主成分分析没有显示出任何明显的趋势，与Hβ轮廓宽度对方向指示的依赖无关，我们也没有发现FRS类星体相对于SRS类星体轮廓基底成分强度从简单的线去混过程中降低的证据。2.双样本测试揭示了类星体和类星体子样本之间的一些强烈差异，包括光学光度紧密匹配的样本之间的差异。虽然类星体在统计上更接近FRS类星体而不是SRS类星体的发射线性质，FRS类星体仍然具有更宽和更红的非对称Hβ轮廓，更强的[O III] λ5007发射和更弱的光学Fe II发射。在FRS和SRS类星体的组合样本中，Hβ轮廓宽度和非对称性参数的方差也明显大于类星体之间的方差。从类星体和类星体的组合样品中，我们证实了在~λλ4434-4684范围内，软X射线光度与Fe II光学发射复合体的等效宽度之间存在着反相关关系。3.几个类星体的巴耳末线剖面显示了两个部分，一个是中间速度宽度（~103 km s-1）的核心，另一个是非常宽的（~104 km s-1）基底，通常相对于系统速度发生红移。这支持了宽线区分为内部甚宽线区和外部中间线区的证据。少数天体也显示出异常强烈的He II λ4686和/或He I λ5876发射，而在其他天体中，这些谱线很弱或不存在。目前还不清楚这些差异是物体固有的，还是代表由宽线气体的动态演化引起的瞬态事件。类星体样本的结果与FRS和SRS类星体的统一模型一致，并解释了剖面宽度的变化来自于对具有强平面运动分量的扁平宽线区域的不同看法。在一个统一的模型下，我们估计平面随机BLR运动的比例为~7：1。假设轮廓宽度和不对称性参数跟踪中心黑洞的质量，这些参数的分布表明，类星体中的平均黑洞质量和黑洞质量的范围比类星体更大，与类星体黑洞是合并星系中心两个或多个黑洞合并的快速旋转产物的模型一致。
We present optical spectrophotometry of 45 quasars in the redshift range 0.045-0.592. These data are combined with the sample of 87 low-redshift quasar and QSO spectra obtained by Boroson & Green for a more extensive investigation of the relation of the properties of the broad Hβ, [O III] λ5007, and optical Fe II emission lines to the objects' radio, optical, and X-ray continuum parameters. We derive a complete correlation matrix for the quasars and perform two-sample tests on the subsamples of flat radio spectrum (FRS) quasars, steep radio spectrum (SRS) quasars, and radio-quiet objects (QSOs). Our principal findings are as follows: 1. We confirm that the width of the Hβ profile at quarter-maximum and half-maximum points is inversely correlated with the ratio of the 6 cm radio core flux to that measured from the optical continuum at 5500 Å, which has been argued to be an indicator of the orientation of the objects' radio axis under beaming models. The Hβ profile widths do not correlate strongly with any line or continuum parameter likely to be an indicator of the intrinsic power of the central engine, including the extended radio luminosity. A principal components analysis of the correlation matrix does not reveal any clear trends separate from the dependence of Hβ profile width on the orientation indicator, and we find no evidence of a decrease in the strength of the profile base component in FRS quasars relative to SRS quasars from a simple line deblending procedure. 2. The two-sample tests reveal several strong differences between the quasar and QSO subsamples, including differences between samples closely matched in optical luminosity. While QSOs are statistically closer to FRS quasars than SRS quasars in their emission-line properties, the FRS quasars still have significantly wider and more redward asymmetric Hβ profiles, stronger [O III] λ5007 emission, and weaker optical Fe II emission. The variance of the Hβ profile width and asymmetry parameters is also significantly larger among the combined sample of FRS and SRS quasars than among the QSOs. From the combined quasar and QSO sample, we confirm that there is an inverse correlation between soft X-ray luminosity and the equivalent width of the optical Fe II emission complex in the range ~λλ4434-4684. 3. The Balmer line profiles of several of the quasars show a division into two components, a core of intermediate (~103 km s-1) velocity width, and a very broad (~104 km s-1) base that is typically redshifted with respect to systemic velocity. This supports evidence that the broad-line region is divided into an inner Very Broad Line Region and an outer Intermediate Line Region. A few objects also display unusually strong emission in He II λ4686 and/or He I λ5876, while in other objects these lines are weak or absent. It is presently unclear whether these differences are intrinsic to the objects or else represent transient events caused by the dynamical evolution of the broad-line gas. The results for the quasar sample are consistent with unified models of FRS and SRS quasars and the interpretation that the change in profile widths arises from differing views of a flattened broad-line region with a strong component of planar motion. Under a unified model we estimate the ratio of planar to random BLR motions to be ~7:1. Assuming that the profile width and asymmetry parameters trace the mass of the central black hole, the distributions of these parameters indicate a larger average hole mass and a larger range of hole masses among the quasars than the QSOs, consistent with the model in which quasar black holes are the rapidly spinning product of the coalescence of two or more black holes at the centers of merged galaxies.