Interferometric 12CO Observations of the Central Disk of NGC 4631: An Energetic Molecular Outflow
Interferometric 12CO Observations of the Central Disk of NGC 4631: An Energetic Molecular Outflow
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NGC 4631 中央圆盘的干涉 12CO 观测：高能分子流出
DOI：
10.1086/308869
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
R. Rand
中科院分区：
文献类型：
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作者：
R. Rand
我们提出的干涉观测CO J = 1-0发射的边缘星系NGC 4631，其扩展的气体晕和潮汐相互作用的中心区域。以前的单碟观测表明，几乎所有的CO排放都来自长度约为4 kpc的中心环或棒状结构。我们在更高的分辨率下确认了这种结构，并发现它在中心弯曲，反映了这个星系在光学图像中明显的整体弯曲。运动学的证据有利于一个刚性旋转的环杆。在几种示踪剂中的气体晕发射集中在该分子结构的上方和下方。在该结构东端的发射峰以北是一个平面外的特征，显示出类似贝壳的性质，我们将其解释为高能分子外流。所涉及的能量很难估计，但可能是1054尔格或更多。在这个结构下面的盘中的CO浓度与明亮的H II区域复合体，射电发射的峰值以及ROSAT HRI地图中看到的星系内盘中最明亮的X射线特征相吻合，所有这些都表明强烈的星星形成。射电连续辐射的丝状体也可能在圆盘的这个区域有一个足迹。外流的来源尚不清楚。
We present interferometric observations of CO J = 1-0 emission in the central regions of the edge-on galaxy NGC 4631, known for its extended gaseous halo and its tidal interactions. Previous single-dish observations revealed that almost all of the CO emission arises from a central ring or barlike structure of length ~4 kpc. We confirm this structure at higher resolution and find that it is bent at the center, reflecting the overall bend in this galaxy apparent from optical images. The kinematic evidence favors a rigidly rotating ring over a bar. The gaseous halo emission in several tracers is concentrated above and below this molecular structure. To the north of an emission peak at the eastern end of the structure is an extraplanar feature showing filamentary and shell-like properties we interpret as an energetic molecular outflow. The energies involved are difficult to estimate but are probably of order 1054 ergs or more. The CO concentration in the disk below this structure coincides with a bright H II region complex, a peak of radio emission, and the brightest X-ray feature in the inner disk of the galaxy seen in a ROSAT HRI map, all suggesting intense star formation. A filament of radio continuum emission may also have a footprint in this region of the disk. The origin of the outflow is unclear.