Origin of early-time optical and ultraviolet emission in tidal disruption events

Determine the physical origin of optical and ultraviolet emission in the early-time phases of tidal disruption events, distinguishing among shock-powered dissipation, reprocessing by extended optically thick material, and related mechanisms.

Background

The paper studies the anisotropic wind generated by nozzle-shock dissipation in a three-dimensional radiation-hydrodynamic simulation of a tidal disruption event involving a 0.5-solar-mass star and a 10^4-solar-mass intermediate-mass black hole. Its results show that shock-powered outflows can reprocess high-energy emission into ultraviolet and optical radiation even in the absence of a central accretion disc.

Despite this result, the broader physical origin of early-time optical and ultraviolet emission in tidal disruption events remains unresolved. Competing models invoke local thermalization of shock energy, reprocessing of hard radiation from an inner accretion flow, quasi-static envelopes, or outflowing winds. The authors explicitly identify the origin of this emission as an open question, motivating further simulations and radiative-transfer studies across different event parameters and physical scenarios.