Document Type


Publication Date

Winter 2-1-1994

Publication Title

The American Astronomical Society


The Astrophysical Journal


The γ-ray burst brightness distribution in inhomogeneous and the distribution on the sky is nearly isotropic. These features argue against an association with γ-ray bursts with those Galactic objects that are known to exhibit a strong concentration toward the Galactic center or plane. The observed statistical properties indicate a cosmological origin. Circumstantial evidence suggests that neutron stars are involved in the burst phenomenon. HEre we consdier Population II neutron stars in an extended Galatic Halo (EGH) as an alternative to cosmological scenaries. The BATSE data indicate a small deviation from isotropy near the 2 σ level of statistical significance. If confirmed for an increasing number of bursts, these anisotropies could rule out cosmological scenarios. On the other hand, EGH models require small anisotropies like those observed by BATSE. We consdier simple distribution models to determine the generic properties such halos must have to be consistent with the observations and discuss the implications of the corresponding distance scale on burst models.