Unveiling the Nature of Fast Blue Optical Transients Through Radio Emission

Liu, Liang-Duan

Previous radio studies of fast blue optical transients (FBOTs) have provided crucial insights into their explosion energetics and circumstellar environments. The prototype event AT2018cow exhibited luminous radio emission, reaching -5 mJyat 8 GHz, which has been interpreted as arising from a fast (v≥0.1c) ejecta interacting with a dense ambient medium. In this work, we present a detailed analysis of the radio emission from FBOTs and demonstrate that reproducing such bright signals requires a moderately relativistic outflow expanding into a structured circumstellar medium with a broken power-law density profile. Our results highlight the importance of both ejecta dynamics and environmental complexity in shaping the observed radio light curves, and provide key constraints on the progenitor systems and explosion mechanisms of FBOTs.