HIGH VELOCITY NEUTRON-STARS AND GAMMA-RAY BURSTS

The observations of the BATSE instrument on the Compton Gamma-Ray Obse rvatory show that the spatial distribution of gamma-ray burst sources is isotropic but radially non-uniform. As is well known, the spectral features, the time histories and the X-ray tails present in some gamma -ray bursts suggest that they may arise from galactic neutron stars. B ut, low velocity neutron stars born in the Galactic disk would concent rate toward the galactic plane and center, and could not fit the BATSE results. However, the high velocity neutron stars with velocity simil ar to 1000 km s(-1) may escape from the Galactic gravitational field a nd form a nearly isotropic distribution. Here we calculate the three s tatistical values of[V/V-max], [sin(2)b] and [cos theta] as functions of the intensities C-max/C-min and find that they could be fitted by t he distribution of high velocity neutron stars under the assumption th at the high velocity neutron stars should turn on as gamma-ray burst s ources only after some time (perhaps after they have ceased to be radi o pulsars). Our calculation shows that the statistical value of [cos t heta] is more sensitive than [sin(2)b] to the angular distribution of high velocity neutron stars, i.e. the deviation of [cos theta] from 0 is more readily detected than the deviation of sin(2)b from 1/3, so we expect that with the increasing sensitivity of instrument and the mor e exact value of [cos theta], it is possible to determine whether this high velocity neutron star model is correct. Some results are discuss ed in the text.