Collapse of neutron stars to black holes in binary systems: A model for short gamma-ray bursts

The accretion of approximate to 0.1 - 1 M-. of material by a neutron star through Roche lobe overflow of its companion or through white dwarf - neutron star coalescence in a low-mass binary system could be enough to exceed the critical mass of a neutron star and trigger its collapse to a black hole, leading to the production of a short gamma-ray burst (SGRB). In this model, SGRBs would often be found in early-type galaxies or in globular cluster environments, though they could also be formed through stellar wind accretion in high-mass binary systems of star-forming galaxies. Although the collapse event is likely to be of short ( << 1 s) duration, afterglow complexity could be produced by neutron decoupling in the fireball and subsequent accretion of the companion remnant, for example, the disrupted white dwarf core.