IS THE NEARBY GALACTIC DISK STILL AN OPTION FOR GRBS

The BATSE experiment has now observed more than 1100 gamma-ray bursts. The observed angular distribution is isotropic, while the brightness distribution of bursts shows a reduced number of faint events. These o bservations favor a cosmological burst origin. Alternatively, very ext ended Galactic halo models are under consideration. Simple Galactic di sk models are essentially ruled out, but a few models still invoke a v ery local disk origin. In the context of these local disk models, the location of the Sun above the Galactic midplane should cause a notable hemispheric asymmetry in the angular distribution and thus a dipole m oment. We introduce the new dipole statistic [sin b] to test for this effect. The value of this dipole moment for the BATSE 3B catalog is in significant, which argues against this class of models.