EFFECTS OF LOCATION UNCERTAINTIES ON THE OBSERVED DISTRIBUTION OF GAMMA-RAY BURSTS DETECTED BY BATSE

The Burst and Transient Source Experiment (BATSE) on NASA's Compton Gamma-Ray Observatory has shown that the sources of gamma-ray bursts have an angular distribution consistent with isotropy, yet the bursts are spatially inhomogeneous (Meegan et al.). Detection of a statistically significant deviation from isotropy in the burst distribution would provide a clue to the distance of the burst sources. BATSE's ability to detect slight deviations of the angular distribution from isotropy is, in part, dependent on the accuracy of the computed burst locations. Using bursts whose locations have been determined accurately and independently by the Third Interplanetary Network, we derive an estimate of the BATSE location uncertainties. We then incorporate these uncertainties into three-dimensional Monte Carlo simulations of the burst distributions to show that, despite individual burst location uncertainties of approximately 5-degrees, the ability of BATSE to place stringent limits on the anisotropy present in the angular distribution of the gamma-ray bursts is not significantly degraded. We conclude with a discussion of the effects on observations of possible galactic halo distributions of the burst sources.