Limits on the Galactic model of gamma-ray bursts

Abstract

The Burst and Transient Source Experiment (BATSE) has shown that the sky distribution of gamma-ray bursts (GRBs) is remarkably isotropic but non-uniform, which implies that the observed bursts may occur either in an extended Galactic halo or at cosmological distances. For the Galactic origin, Hartmann and Narayan have argued that the rotational energy of neutron stars is insufficient by orders of magnitude to provide the observed burst rate. The present authors have calculated the period distribution of dead pulsars and found that the rotational energy of neutron stars may indeed be insufficient to account for the total observed energy of the bursts, because only a small fraction (~I/l p) of rotational energy can be converted into gamma-rays if GRBs are produced by glitches. Furthermore, it is difficult to establish high-velocity neutron stars as a subclass of observed gamma-ray bursts since the observed burst rate is small, ~10 yr -1