The other possible galactic solution is given by an extended halo around our Galaxy. This structure should be large enough to account for the GRB isotropy, compensating for the off-center position of our Solar System with respect to the Galaxy. This lower limit is set at about 125 kPc. On the other hand, if this halo would be largely extended we should observe it in the close-by Andromeda galaxy. The absence of this observation places the upper limit at about 400 kPc ([Hakkila et al. 1994]). The main concern on this geometrical location is that the existence of the extended halo must be postulated ad-hoc for the GRBs, since no evidence for it is gained for any other class of celestial objects.
However, if the GRBs are emitted at a distance of the order of 100 kPc, then the observed intensities imply an intrinsic luminosity of the order of 1042 erg s-1. This amount of energy can be easily obtained from compact galactic objects (i.e. neutron stars) undergoing non-destructive phenomena, like internal reassessment or surface explosions. The most common scenario in this case would be a thermal cooling of the star surface after the GRB explosion.