Evolutions of stellar-mass black hole hyperaccretion systems in the center of gamma-ray bursts

TL;DR

This paper models the evolution of neutrino-dominated accretion disks around stellar-mass black holes to explain gamma-ray burst energies, highlighting the importance of black hole spin and accretion rates in powering different GRB types.

Contribution

It provides a time-dependent analysis of neutrino annihilation luminosity in hyperaccretion systems, linking black hole evolution to GRB energetics and suggesting the necessity of alternative processes for high-luminosity bursts.

Findings

Total neutrino annihilation energy can account for most short and half of long GRBs.

Extreme Kerr black holes are likely in high-luminosity GRB engines.

High-energy GRBs may require additional MHD processes like the Blandford-Znajek mechanism.

Abstract

A neutrino-dominated accretion disk around a stellar-mass black hole (BH) can power a gamma-ray burst (GRB) via annihilation of neutrinos launched from the disk. For the BH hyperaccretion system, high accretion rate should trigger the violent evolution of the BH's characteristics, which further leads to the evolution of the neutrino annihilation luminosity. In this paper, we consider the evolution of the accretion system to analyze the mean time-dependent neutrino annihilation luminosity with the different mean accretion rates and initial BH parameters. By time-integrating the luminosity, the total neutrino annihilation energy with the reasonable initial disk mass can satisfy the most of short-duration GRBs and about half of long-duration GRBs. Moreover, the extreme Kerr BH should exist in the cental engines of some high-luminosity GRBs. GRBs with higher energy have to request the alternative magnetohydrodynamics processes in the centers, such as the Blandford-Znajek jet from the accretion system or the millisecond magnetar.