Periodic Reporting for period 1 - TackTDEs (Tackling the complexity of Tidal Disruption Events)
Okres sprawozdawczy: 2021-02-01 do 2023-01-31
A star that gets too close to a supermassive black hole gets torn apart into an elongated stream of gaseous debris by strong tidal forces. About a hundred of these tidal disruption events (TDEs) have been discovered to date and a much larger number is expected from current and future missions such as eROSITA and the Rubin Observatory. The powerful flare of light emitted during this process encodes rich information about the properties of the disrupting black hole, which could in particular be used to get insight into how these gargantuan objects formed at the center of galaxies. In order to fully exploit this predictive power, the aim of the project is to study the gas evolution during these events to reach a full theoretical characterization of their observational signatures. By developing new approaches to this problem, the researcher has been able to study for the first time the most crucial phases of this evolution and the mechanisms at the origin of the detectable signal, which paves the way to an optimal exploitation of the large number of future observations.
Through a combination of analytical tools and computer simulations, the researcher was able to study the entire evolution of the gas stripped from the star to characterize the observational signatures from TDEs. He has evaluated the geometry of the stream of stellar debris as it evolves around the black hole, and studied with computer simulations the subsequent phase of black hole fueling through an accretion disc, during which most of the observable radiation gets emitted. These important advances have been presented at various international conferences and they are currently applied to interpret observations for newly discovered events,
While previous works have not been able to follow the entire gas evolution in TDEs within a single computer simulations due to the too high computational power required, the researcher has developed a new strategy that consists in dividing this evolution into successive steps that can each be simulated, and then assembled to get insight into the full evolution. Using this innovative technique, he was able to study several crucial physical mechanisms for the first time, which led to a robust theoretical paradigm for how these events take place, and a characterization of the resulting observable signatures. This work paves the way to a full exploitation of the large number of TDE observations to be made by instruments such as eROSITA and the Rubin Observatory, which will unleash the full predictive power of these events.