Counter-rotation and High-velocity Outflow in the Parsec-scale Molecular Torus of NGC 1068
Counter-rotation and High-velocity Outflow in the Parsec-scale Molecular Torus of NGC 1068
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NGC 1068 秒差距级分子环中的反向旋转和高速流出
DOI：
10.3847/2041-8213/ab3c64
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
E. Sani
中科院分区：
文献类型：
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作者：
C. Impellizzeri;J. Gallimore;S. Baum;M. Elitzur;R. Davies;D. Lutz;R. Maiolino;A. Marconi;R. Nikutta;C. O’Dea;E. Sani
本文报道了NGC 1068分子环中256 GHz核射电连续谱和HCN（J = 3 → 2）的1.4pc分辨率观测结果。集成无线电连续谱发射具有与自由发射一致的平坦光谱，并分解成类似于边缘增亮双锥体的X形结构。HCN在连续谱的吸收中被检测到，吸收光谱显示出明显的蓝色翅膀，表明高速分子流出，速度达到450 km s−1。离核发射线的运动学和形态学分析揭示了两个嵌套的，旋转的磁盘组件。内盘在r = 1.2 pc的范围内，其运动学与在开普勒旋转中围绕中心质量为1.66 × 107 M <$o的几乎边缘上、几何上薄的H2O超脉泽盘一致。外盘，它延伸到107 pc半径，相对于内盘反向旋转。外盘的旋转曲线与超脉泽盘围绕相同中心质量的旋转一致，但方向相反。分子气体的形态在核连续谱源周围是不对称的。我们推测外盘是由最近引入的分子气体从宿主星系或捕获的矮卫星星系中脱落而形成的。在NGC 1068中，我们发现了直接的证据，表明分子环面由秒差距尺度上的反向旋转和错位盘组成。
We present 1.4 pc resolution observations of 256 GHz nuclear radio continuum and HCN (J = 3 → 2) in the molecular torus of NGC 1068. The integrated radio continuum emission has a flat spectrum consistent with free–free emission and resolves into an X-shaped structure resembling an edge-brightened bicone. HCN is detected in absorption against the continuum, and the absorption spectrum shows a pronounced blue wing that suggests a high-velocity molecular outflow with speeds reaching 450 km s−1. Analysis of the off-nucleus emission line kinematics and morphology reveals two nested, rotating disk components. The inner disk, inside r ∼ 1.2 pc, has kinematics that are consistent with the nearly edge-on, geometrically thin H2O megamaser disk in Keplerian rotation around a central mass of 1.66 × 107 M⊙. The outer disk, which extends to ∼7 pc radius, counter-rotates relative to the inner disk. The rotation curve of the outer disk is consistent with rotation around the same central mass as the megamaser disk but in the opposite sense. The morphology of the molecular gas is asymmetric around the nuclear continuum source. We speculate that the outer disk formed from more recently introduced molecular gas falling out of the host galaxy or from a captured dwarf satellite galaxy. In NGC 1068, we find direct evidence that the molecular torus consists of counter-rotating and misaligned disks on parsec scales.