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arXiv 0905.1450astro-ph.GA
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从HI功率谱测量NGC 1058的标度高度

The Scale Height of NGC 1058 Measured from its HI Power Spectrum

Prasun Dutta, Ayesha Begum, Somnath Bharadwaj, Jayaram N. Chengalur

备注：
Accepted for publication in Mon. Not. of Royal Astron. Soc. Letters
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摘要：

利用射电干涉观测，我们测量了近正面螺旋星系NGC 1058的HI功率谱。功率谱很好地拟合两个不同的功率定律$P(U)=AU^α$，一个与$α=- 2.5\pm 0.6$在小长度尺度$(600 {\rm pc} {\rm to} 1.5 {\rm kpc})$和另一个与$α=- 1.0\pm 0.2$在大长度尺度$(1.5 {\rm kpc} {\rm to} 10.0 {\rm kpc})$。我们解释这种变化的斜率的功率谱作为一个过渡，从3D湍流在小的长度尺度的2D湍流在大的长度尺度的星系盘的平面。我们使用观察到的功率谱的中断来估计星系的标度高度，我们发现是$ 490 \pm 90 $ pc。

英文摘要：

We have measured the HI power spectrum of the nearly face-on spiral galaxy NGC 1058 from radio-interferometric observations using a visibility based estimator. The power spectrum is well fitted by two different power laws $P(U)=AU^α$, one with $α=- 2.5\pm 0.6$ at small length-scales $(600 {\rm pc} {\rm to} 1.5 {\rm kpc})$ and another with $α=- 1.0\pm 0.2$ at large length-scales $(1.5 {\rm kpc} {\rm to} 10.0 {\rm kpc})$. We interpret this change in the slope of the power spectrum as a transition from 3D turbulence at small length-scales to 2D turbulence in the plane of the galaxy's disk at large length-scales. We use the observed break in the power spectrum to estimate the galaxy's scale-height, which we find to be $ 490 \pm 90 $ pc.

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