Hot tori around black holes as sources of gamma ray bursts

TL;DR

This paper explores hot tori around stellar black holes as potential gamma ray burst sources, analyzing different models and their energy outputs, and concludes that certain merger models are unlikely sources.

Contribution

It introduces new models of hot tori around Kerr black holes with varied angular momentum and entropy, assessing their viability as gamma ray burst sources.

Findings

Neutron star merger models produce insufficient energy for gamma ray bursts.

High angular momentum black holes and constant angular momentum tori are promising sources.

Collapse of rapidly rotating WR stars remains a plausible gamma ray burst source.

Abstract

We investigate the configurations consisting of massive, dense and hot tori around stellar mass Kerr black holes as possible sources of energy for the gamma ray bursts in cosmological hypothesis of their origin. We limit parameters of our models to the values resulting from neutron stars merger calculations or suggested in the ``failed supernova'' scenario. We investigate models with different angular momentum distributions and different specific entropies. We construct also approximate evolutionary tracks of our systems postulating some viscosity mechanism to be present. We find, that models resulting from a merger of two neutron stars give too little energy to be likely sources of gamma ray bursts. This conclusion remains true despite the artificially high values of specific entropy and viscosity, which we use in our calculations. The promising models should contain a high angular momentum black hole ($a \sim 1$) and/or a torus with almost constant specific angular momentum. The configurations resulting from a collapse of rapidly rotating WR stars are not excluded as sources of the bursts due to a greater freedom in choosing their initial parameters.