A New, Kinematically Anomalous H I Component in the Spiral Galaxy NGC 2403
A New, Kinematically Anomalous H I Component in the Spiral Galaxy NGC 2403
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螺旋星系 NGC 2403 中一个新的运动异常 H I 分量
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
G. van Moorsel
中科院分区：
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作者：
F. Fraternali;T. Oosterloo;R. Sancisi;G. van Moorsel
我们讨论了螺旋星系NGC2403的新的、高灵敏度的HI观测，它显示出相对于“冷”盘以反常速度扩展的发射。这种“反常”气体成分(~1/10)可能位于晕区，其自转速度比盘中气体慢(约20-50公里S-1)。此外，它还显示了速度场的扭曲，我们将其解释为向银河系中心的大规模径向运动(S-1流入10-20公里)。对于它的起源和运动学，最可能的解释似乎是银河系喷泉。然而，有很大一部分反常气体似乎在与自转相反的方向运动，在这样的照片中很难理解。在NGC2403中发现的这些异常气体复合体可能类似于我们银河系的高速云。它们可能在螺旋星系中相当常见，由于缺乏敏感性，目前还没有被检测到。
We discuss new, high-sensitivity H I observations of the spiral galaxy NGC 2403, which show extended emission at anomalous velocities with respect to the "cold" disk. This "anomalous" gas component (~1/10 of the total H I mass) is probably located in the region of the halo and rotates more slowly (~20-50 km s-1) than the gas in the disk. Moreover, it shows a distortion in the velocity field that we interpret as a large-scale radial motion (10-20 km s-1 inflow) toward the center of the galaxy. The most likely explanation for its origin and kinematics seems to be that of a galactic fountain. There is, however, a significant part of the anomalous gas that seems to be moving contrary to rotation and is difficult to understand in such a picture. These anomalous gas complexes discovered in NGC 2403 may be analogous to the high-velocity clouds of our Galaxy. They may be rather common in spiral galaxies and not have been detected yet for lack of sensitivity.