Explaining GRB features through MAD black hole spin-down
Speaker: Aleksander Lenart (Jagiellonian University)
Abstract:
Recent developments in numerical general relativity magnetohydrodynamics have shown that a fast-spinning black hole (BH) surrounded by a magnetically arrested disk (MAD) will lose its angular momentum due to jet energy extraction. The magnetic field in the disk causes turbulence, which significantly lowers the specific angular momentum of the matter. Therefore, the energy extraction dominates over angular momentum delivery, and the BH loses its spin. In a recent paper by my team, we applied those findings to the data of Gamma-ray Bursts (GRBs). Those sources are primarily produced in the high-mass star core-collapse, resulting in the creation of a compact central object like a BH or a magnetar. Some GRBs exhibit an extreme energy budget of>10^53 erg, which is above the maximum possible energy of a magnetar. Therefore, for some sources, the BH-powered emission is the only known mechanism that could explain observations. I will demonstrate how such a scenario allows us to model GRB light curves, and how it predicts the Dainotti correlation. The anti-correlation between the duration of the plateau phase in the light curve and its luminosity. I will discuss the typical masses of BHs that could have been created in GRB events and the possible connection with the gravitational wave observations.