论文标题
螺旋星系NGC 5236中大规模能量级联的证据
Evidence of large scale energy cascade in the spiral galaxy NGC 5236
论文作者
论文摘要
湍流在星系的结构和动力学中起着重要作用，并影响其中的各种过程，包括恒星形成。在这项工作中，我们研究了外部螺旋星系NGC 5236的大规模湍流特性。我们将VLA多配置档案数据与新的GMRT观察结果结合在一起，以估算近二十几十几十几十个长度尺度的星系的视觉速度波动功率光谱的柱密度和视线速度波动线。 ISM湍流的能量输入量表约为$ 6 $ kpc。银河磁盘中二维湍流的功率谱遵循圆柱密度的斜率$ -1.23 \ pm0.06 $，视线速度的$ -1.23 \ pm0.06 $。测得的功率光谱强烈建议以$ \ sim 7 \ times 10^{ - 11} $ erg cm $^{ - 2} $ sec $ sec $^{ - 1} $的稳定能量输入的压缩强迫。我们得出的结论是，其中大部分源于磁盘中的重力不稳定性和自我重力。这是对任何外部螺旋星系的湍流统计数据的第一项也是最全面的研究。
Turbulence plays an important role in the structure and dynamics of the galaxy and influences various processes therein including star formation. In this work, we investigate the large scale turbulence properties of the external spiral galaxy NGC 5236. We combine the VLA multi-configuration archival data with the new GMRT observation to estimate the column density and line of sight velocity fluctuation power spectra for this galaxy over almost two decades of length scales. The energy input scale to the ISM turbulence is found to be around $6$ kpc. Power spectra of the two-dimensional turbulence in the galaxy's disk follow a power law with a slope $-1.23\pm0.06$ for the column density and $-1.91\pm0.08$ for the line of sight velocity. The measured power spectra slopes strongly suggest in favour of a compressive forcing with a steady energy input of $\sim 7 \times 10^{-11}$ erg cm$^{-2}$ sec$^{-1}$. We conclude that much of these originate from the gravitational instabilities and self-gravity in the disk. This is the first and most comprehensive study of turbulence statistics for any external spiral galaxy.
