The scaleheight of NGC 1058 measured from its H I power spectrum

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(alpha), one with alpha = -2.5 +/- 0.6 at small length-scales (600 pc to 1.5 kpc) and another with alpha = -1.0 +/- 0.2 at large length-scales (1.5-10.0 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 disc at large length-scales. We use the observed break in the power spectrum to estimate the galaxy's scaleheight, which we find to be 490 +/- 90 pc.