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Arxiv: Power Spectra of JWST images of Local Galaxies: Searching for Disk Thickness Published: 11/10/2024 10:54:56 PM Updated: 11/10/2024 10:54:56 PM

Paper abstract: JWST/MIRI images have been used to study the Fourier transform power spectra(PS) of two spiral galaxies, NGC 628 and NGC 5236, and two dwarfs, NGC 4449 andNGC 5068, at distances ranging from 4 to 10 Mpc. The PS slopes on scales largerthan 200 pc range from -0.6 at 21 microns to -1.2 at 5.6 microns, suggesting ascaling of region luminosity with size as a power law with index ranging from2.6 to 3.2, respectively. This result is consistent with the size-luminosityrelation of star-forming regions found elsewhere, but extending here to largerscales. There is no evidence for a kink or steepening of the PS at sometransition from two-dimensional to three-dimensional turbulence on the scale ofthe disk thickness. This lack of a kink could be from large positionalvariations in the PS depending on two opposite effects: local bright sourcesthat make the slope shallower and exponential galaxy profiles that make theslope steeper. The sources could also be confined to a layer of molecularclouds that is thinner than the HI or cool dust layers where PS kinks have beenobserved before. If the star formation layers observed in the near-infraredhere are too thin, then the PS kink could be hidden in the broad tail of theJWST point spread function.