THE DIFFERENCES IN THE TORUS GEOMETRY BETWEEN HIDDEN AND NON-HIDDEN BROAD LINE ACTIVE GALACTIC NUCLEI
THE DIFFERENCES IN THE TORUS GEOMETRY BETWEEN HIDDEN AND NON-HIDDEN BROAD LINE ACTIVE GALACTIC NUCLEI
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DOI：
10.1088/0004-637x/803/2/57
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发表时间：
2015-01
期刊：
影响因子：
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通讯作者：
K. Ichikawa;C. Packham;C. R. Almeida;A. Ramos;A. Alonso-Herrero;O. González-Martín;E. Lopez-Rodriguez-E.-Lopez
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文献类型：
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作者：
K. Ichikawa;C. Packham;C. R. Almeida;A. Ramos;A. Alonso-Herrero;O. González-Martín;E. Lopez-Rodriguez-E.-Lopez
本文给出了用块状环面模型对21个活动星系核的红外光谱能量分布进行拟合的结果。我们从文献中汇编了高空间分辨率(∼0.30.7arcsec)中IR(MIR)N波段光谱、Q波段成像以及核近红外和MIR光度学。结合这些核的近和MIR观测，远红外测光，以及块状环面模型，使我们能够对环面性质和几何形状施加约束。我们根据宽线区域(BLR)的性质将样本分为三种类型：类型1S，先前观察到的具有散射或隐藏的宽线区域(HBLR)的类型2S，以及没有任何公布的HBLR签名的类型2S(NHBLR)。通过比较环面模型参数，我们可以得到每个亚群的第一个定量环面几何视图。我们发现NHBLR活动星系核比HBLR活动星系核具有更小的环面张开角和更大的覆盖因子。这表明，在NHBLR中观测到来自BLR的散射(极化)通量的机会可能受到以下双重效应的影响：(A)由于环面张开角度小，散射介质减少，以及(B)观察者和散射区之间的环面遮盖度增加。这些效应给出了在某些2型活动星系核中没有观察到HBLR的合理解释。
We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy torus models. We compiled high spatial resolution (∼0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy torus models enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus model parameters gives us the first quantitative torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small torus opening angle and (b) the increased torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.