演講資訊

摘要：

2003fg-like Type Ia supernovae are rare and brighter in the ultraviolet (UV) than normal Type Ia supernovae. We analyzed UV spectra of four such events using Swift. While their spectral composition is similar to normal Type Ia supernovae, they show significantly more UV flux. This UV excess cannot be explained by their host galaxy properties. Instead, we find that a hot component—possibly from interaction with surrounding material—can account for the UV excess, suggesting these explosions happen in dense, CSM-rich environments.