Oral Presentation
Simulating multiwavelength spectra and images of cosmic ray driven winds
Presenter: Huai-Hsuan Chiu (University of Michigan)
Formation of galaxies is significantly influenced by galactic winds, possibly driven by cosmic rays due to their long cooling time and better coupling to plasma compared to radiation. In this study, we compare the radio observations of the edge-on galaxy NGC 4217 from the CHANG-ES collaboration catalog with a mock observation of an isolated galaxy based on the AREPO simulation that adopts the state-of-the-art two-moment cosmic ray transport treatment and multiphase ISM model. We find significant qualitative and quantitative agreement between the simulated and observed images and spactroscopic data. Specifically, we find that (i) the simulated emission maps match observations much better than previous studies and the shapes of intensity profiles are only very weakly dependent on the normalization of the magnetic field; (ii) the simulated radio polarization images exhibit X-shaped morphology, often seen in edge-on galaxies, which is consistent with the presence of a galactic-scale outflow; and (iii) the multiwavelength spectrum above 0.1 GHz is in agreement with the observations. This qualitative match is possible provided that the simulated magnetic field is moderately boosted, which could be attributed to the galactic disk interaction with the CGM. Our results highlight the importance of incorporating advanced cosmic ray transport models in simulations, and provide a deeper understanding of galactic wind dynamics and its impact on galaxy evolution.
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