Southern Galactic Plane Survey Measurements of the Spatial Power Spectrum of Interstellar H I in the Inner Galaxy
Southern Galactic Plane Survey Measurements of the Spatial Power Spectrum of Interstellar H I in the Inner Galaxy
复制标题
内星系星际 H I 空间功率谱的南银道平面巡天测量
DOI：
10.1086/323409
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
A. Green
中科院分区：
文献类型：
--
作者：
J. Dickey;N. McClure;S. Stanimirović;B. Gaensler;A. Green
利用南银道面巡天的数据，我们测量了银河系第四象限星际中性氢原子的空间功率谱。该函数显示了与在银河系第二象限和麦哲伦云中发现的H I相同的幂律行为，具有相同的斜率。当我们在比典型的小尺度速度色散更宽的速度间隔上求平均值时，我们发现，如果柱密度波动受小空间尺度上气体密度变化的支配，则如星际湍流理论所预测的那样，暖气体的斜率会变陡，从λ-3到λ-4。冷气体显示出不同的斜率增加，这表明它是在由速度场中的波动主导的湍流的制度。总体而言，这些结果证实中性原子介质中的小尺度结构和运动可以通过动能的湍流级联很好地描述。
Using data from the Southern Galactic Plane Survey, we have measured the spatial power spectrum of the interstellar neutral atomic hydrogen in the fourth Galactic quadrant. This function shows the same power-law behavior that has been found for H I in the second quadrant of the Milky Way and in the Magellanic Clouds with the same slope. When we average over velocity intervals broader than the typical small-scale velocity dispersion, we find that the slope steepens, from ≃-3 to ≃-4 for the warm gas, as predicted by theories of interstellar turbulence if the column density fluctuations are dominated by variations in the gas density on small spatial scales. The cool gas shows a different increase of slope, which suggests that it is in the regime of turbulence dominated by fluctuations in the velocity field. Overall, these results confirm that the small-scale structure and motions in the neutral atomic medium are well described by a turbulent cascade of kinetic energy.