Xiaoshan Huang, University of Virginia
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Abstract: The disruption of a star by the tidal force from a nearby supermassive blackhole can power a bright transient flare in multiple wavebands that lasts a few weeks to months. The processes that shape the detected emission from such tidal disruption events (TDE) are an unresolved puzzle. In this talk, I will discuss emission mechanisms in TDEs with series of 3D radiation hydrodynamical simulations, focusing on early time. We find that the stream-stream collision plays an important role in producing early emission as well as impacting later gas dynamics. The strong radiation released in collisions can drive an aspherical optically thick outflow that extends to larger radius, creating early photosphere evolution roughly consistent with optical-ultraviolet observations. I will describe how the gas dynamics depends on the strength of the stream-stream collision. If the radiatively driven outflow significantly modifies the gas distribution, circularization and accretion might not always be prompt, leading to diverse and complex post shock dynamics.