> The authors found previously that GRBs are more frequent in low-mass galaxies such as the Small Magellanic Cloud with a small fraction of elements heavier than hydrogen and helium. This reduces the GRB hazard in the Milky Way by a factor of 10 compared with the overall rate.

Smaller galaxies are deadlier, got it. Is this because GRBs tend to emanate from the galactic centre? And larger galaxies, having more stars further from the centre, have more "habitable" space? Or does it have to do with the higher frequency of heavy elements in large galaxies? If the latter, how do heavy element concentrations cause or moderate GRB activity?