Probing Turbulence in the Interstellar Medium of Galaxies

The power spectrum of HI intensity fluctuation of the interstellar medium carries information of the turbulence dynamics therein. We present a method to estimate the power spectrum of HI intensity fluctuation using radio interferometric observations. The method involves correlating the visibilities in the u-v plane at different baselines. This method is particularly use full for evaluating the power spectrum for the faint dwarf galaxies. We apply this method to 3 spiral galaxies and 5 dwarf galaxies. The measured power spectrum seem to follow a power law P_HI(U) = A U^\alpha, suggesting turbulence to be operational. Further, depending on the slope of the power spectrum, we expect the presence of 2D and 3D turbulence in those galaxies.