Neutrino pair annihilation driven jets from black-hole torus systems

TL;DR

This study uses advanced simulations to explore how neutrino pair annihilation can produce relativistic jets from black hole-torus systems, shedding light on their potential role in certain gamma-ray bursts.

Contribution

The paper presents the first comprehensive general relativistic radiation-hydrodynamics simulations with full neutrino transport across diverse black hole and torus parameters.

Findings

Neutrino pair annihilation can generate relativistic fireballs in most models.

The outflows have energies up to 10^{51} erg and last less than 0.2 seconds.

The results suggest a possible explanation for some low-luminosity short gamma-ray bursts.

Abstract

We perform axisymmetric general relativistic radiation-viscous hydrodynamics simulations of black hole (BH)-torus systems with full Boltzmann Monte-Carlo neutrino transport to investigate the role of neutrino-antineutrino pair annihilation in launching relativistic outflows. Our models span a wide range of BH spins, torus masses, and viscosity parameters. We find that the pair annihilation leads to the formation of relativistic fireballs in most cases, except for those with low black-hole spin and high viscosity. The isotropic-equivalent energies of these outflows reach $\lesssim 10^{51}\,{\rm erg}$ with durations $\lesssim 0.2\,{\rm s}$. While this is insufficient to explain the brightest short gamma-ray bursts (sGRBs), our results suggest that the pair annihilation may account for some low-luminosity sGRBs and GRB precursors. We also provide updated scaling relations for the pair annihilation energy deposition rate as a function of accretion rate, and discuss the sensitivity of outflow properties to numerical resolution and floor density.