The role of black hole spin and magnetic field threading the unstable neutrino disk in Gamma Ray Bursts

TL;DR

This paper investigates how black hole spin and magnetic fields influence the properties and stability of neutrino-cooled accretion disks in Gamma Ray Bursts, highlighting the effects of rapid rotation and energy transfer mechanisms.

Contribution

It provides a detailed numerical analysis of stationary tori around Kerr black holes, incorporating advanced microphysics and magnetic coupling effects, advancing understanding of GRB central engines.

Findings

Rapid black hole spin enhances thermal instability in the torus.

Magnetic coupling facilitates energy transfer from black hole to disk.

Instability occurs at lower accretion rates for fast-spinning black holes.

Abstract

We report on the third phase of our study of the neutrino-cooled hyperaccreting torus around a black hole that powers the jet in Gamma Ray Bursts. We focus on the influence of the black hole spin on the properties of the torus. The structure of a stationary torus around the Kerr black hole is solved numerically. We take into account the detailed treatment of the microphysics in the nuclear equation of state that includes the neutrino trapping effect. We find, that in the case of rapidly rotating black holes, the thermal instability discussed in our previous work is enhanced and develops for much lower accretion rates. We also find the important role of the energy transfer from the rotating black hole to the torus, via the magnetic coupling.