Notice the strong concentration of objects toward the galactic plane, typical for the distribution of distant stars. At larger distances, between our inner solar system and the closest stars, the only known objects are the comets in the Oort cloud. If the bursts came from the Oort cloud, then we should have seen by now the effect of these tidal distortions in the sky distribution of the bursts, and we have not. Once we get out of the solar system we encounter nearby stars, which are distributed more or less uniformly in space, apart from their tendency to 'cluster' in binaries and multiple systems. The distribution over the sky is almost isotropic, as shown in Fig.
Some apparent clustering is due to non-uniformity of the search procedure.
Among distant objects which are readily detected across the galaxy and which are related to stars of moderate mass are the planetary nebulae, the remnants of old red supergiants. The ones older than a few thousand years expanded so much that they are too diffuse to see. The nuclei of the nebulae, former cores of red supergiants, are on their way to become white dwarfs. Planetary nebulae are very bright, and readily discovered out to large distances. Notice the strong concentration toward the galactic plane of these galactic disk objects.