Learning Transient Universe in Near-ultraviolet by Wide-angle Cameras

We perform a detailed analysis and simulations on the transient detection capability in the near-ultraviolet (NUV) band by focusing on some major local transient events. These events include the tidal disruption event due to a supermassive black hole, the shock breakout of a core-collapse supernova and the flare of a late-type star. Our simulations show that a set of small, wide-angle NUV cameras can allow us to detect and study numerous galactic and extragalactic transient events. Based on the analysis and simulations, here we propose a space-based NUV sky patrol mission by updating the proposal that was originally submitted to the Chinese Space Station mission in 2011. The mission proposed here is composed of a set of eight small wide-field NUV cameras each with a diameter of 20 cm. The total sky area simultaneously covered by the NUV cameras is as large as 3000 deg(2). The survey cadence ranges from 30 to 300 s. The transient events are required to be detected by a dedicated onboard software in real time.