MODEL FOR NONSPHERICAL COLLAPSE AND FORMATION OF BLACK-HOLES BY EMISSION OF NEUTRINOS, STRINGS, AND GRAVITATIONAL-WAVES

We present a general relativistic exact model for the spacetime extern al to an axisymmetric bounded distribution of collapsing matter whose rate of mass decrease is a constant that, when vanishing, yields a Sch warzschild solution. Einstein's field equations actually require the e xistence of a timelike shell in the equatorial plane, whose stress-ene rgy tensor is constituted by two independently conserved terms, corres ponding to the emission of neutrinos and strings on the shell. An exte nsion of this model can be achieved to include the emission of gravita tional waves that provides a mechanism by which the rate of mass decre ase goes to zero with the formation of a Schwarzschild black hole.