Speaker
Description
Tidal disruption events (TDEs) occur when a supermassive black hole’s (SMBH) gravitational pull tears a star apart, resulting in a bright burst of electromagnetic radiation. These events provide important information about the environment of SMBHs. When the star is disrupted, some of its material forms an accretion disk around the black hole, emitting radiation as it heats up. However, the actual X-ray radiation of the disk is somehow “reprocessed” into optical bands, a phenomenon which is still unclear; therefore, there are various models for description. According to one of the models, when the fallback rate of the matter exceeds the super-Eddington limit, it creates an optically thick super-Eddington wind, which is responsible for the reprocessing. The exact ratio of the matter leaving with the wind to the amount bound in the disk is not well understood, hence further investigation of the Super Eddington Disk models is necessary.
The main goal of my work is implementing this super-Eddington slim disk model and study the connection between the disk and the wind. This requires solving an ordinary differential equation system in the horizontal direction, as well as the vertical direction, which leads to a nested univariate boundary value problem. Accordingly, I implemented a solving algorithm for these type of problems in C language. This consists of the shooting method for solving the boundary value problem in which the iterations are solved by the Brent's method, and a 4th order Runge-Kutta method was implemented to integrate the differential equations. To validate my code, I solve the Shakura-Sunyaev thin disk model similarly to the Super-Eddington slim disk. This means that I lift most of the analytical assumptions in the equations leading to a nested version of the equations, where the vertical and horizontal solutions depend on each other, analogously to the slim disk model.
The model presented here will be extended to include the wind and convection in the future to describe the Super-Eddington state. This implementation will potentially enables better insights into the connection between the disk and the wind in the context of TDEs.