Cosmic-Ray Electron Propagation in NGC 3044 from Radio Continuum Observations

Abstract Star-forming edge-on galaxies often exhibit extended halo radiation in multiple bands, providing ideal laboratories for studying the transfer of matter from the disk to the halo. We investigate the transport of cosmic-ray electrons (CREs) and the associated galactic wind, and assess their impact on the surrounding medium for NGC 3044. We obtained an NGC 3044 total intensity image at 943 MHz from Australian SKA Pathfinder (ASKAP) observations with a resolution of 16″ and an rms noise of 20 μ Jy beam −1 . The sensitivity is higher than for previous observations at similar frequencies. We find that the ASKAP intensity profiles perpendicular to the disk can be fit with two exponential components. The scale heights of the thin and thick disks are 0.43 ± 0.13 kpc and 1.91 ± 0.26 kpc, respectively. By jointly fitting the total intensity and spectral index profiles with 1D advection and diffusion models, we find that CREs are advected outward from the disk, with the velocity increasing with height as a power law. Beyond ∼3 kpc, the velocity exceeds the escape speed of ∼400 km s −1 , indicating a strong wind. We further identify a possible superbubble of radius ∼3 kpc filled with soft-X-ray-emitting hot gas and surrounded by an H i shell and a bright H α rim. These results demonstrate that radio continuum observations provide a powerful probe of CR-driven winds in normal star-forming spiral galaxies.