The Large Magellanic Cloud (LMC) is the biggest satellite galaxy of the Milky Way and provides a unique laboratory for high-energy astrophysics and dark matter physics. In this work, we develop an end-to-end numerical description of the cosmic-ray (CR) transport and of the associated nonthermal emission in the LMC, extending the public dragon and hermes codes. Within this framework, we compute the diffuse synchrotron radiation of CR electrons in the LMC, and compare the predictions with observed low-frequency radio maps. Because electron diffusion imprints a characteristic morphology on the radio signal, these comparisons enable us to infer the effective average of the LMC diffusion coefficient. We find $D_0=3–6\times {10}^{28}{\mathrm{cm}}^2/\mathrm{s}$ at 1 GeV, which is comparable to, but slightly larger than, values typically obtained for the Milky Way. More generally, this work provides a scalable tool for interpreting nonthermal signals in nearby galaxies and constraining their CR transport.

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• Cosmic ray propagation
• Cosmic rays & astroparticles