Galactic halo model for gamma-ray bursts from high-velocity neutron stars

Abstract

We show that an extened Galactic halo model for gamma‐ray bursts (GRBs) originating from high‐velocity neutron stars (hvns) (≥800 km s−1) with special bursting properties can satisfy the angular isotropy and non‐uniform brightness distribution of GRBs observed by BATSE and PVO. Lower velocity neutron stars are required, however, to burst very rarely in this model. hvns from both the galactic disk and globular clusters are considered. The effects from nearby galaxies, such as the LMC, SMC and M31, are found to be small if the sampling distance for BATSE is ∼100 kpc. The expected rate for detecting X‐ray Flashes associated with GRBs from M31, using an X‐ray detector like the ROSAT PSPC, is ≪1 per day. This model implies that the distribution of the brightest bursts with fluxes ≥3×10−5 ergs cm−2 s−1 may be anisotropic.