 Solution

A neutron star merger, or a neutron star tidally disrupted by a black hole outside its capture region, can leave a hot accretion disk around the remnant. Rapid accretion can power a relativistic jet and a short gamma-ray burst. Beaming means that an observer must lie sufficiently near the jet axis, and not every merger produces an observable burst. A clean binary black hole merger has no substantial baryonic fuel and is not ordinarily expected to power this mechanism. Disruption in a neutron-star–black-hole pair depends on binary mass ratio, black-hole spin and the neutron star's stellar radius.