HOT TORI AROUND BLACK-HOLES AS SOURCES OF GAMMA-RAY BURSTS

We investigate the configurations consisting of massive, dense and hot tori around stellar mass Kerr black holes as possible sources of ener gy for the gamma ray bursts in cosmological hypothesis of their origin . We limit parameters of our models to the values resulting from neutr on stars merger calculations or suggested in the ''failed supernova'' scenario. We investigate models with different angular momentum distri butions and different specific entropies. We construct also approximat e evolutionary tracks of our systems postulating some viscosity mechan ism 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 ra y bursts. This conclusion remains true despite the artificially high v alues of specific entropy and viscosity, which we use in our calculati ons. The promising models should contain a high angular momentum black hole (a similar to 1) and/or a torus with almost constant specific an gular momentum. The configurations resulting from a collapse of rapidl y rotating WR stars are not excluded as sources of the bursts due to a greater freedom in choosing their initial parameters.