re: Question on Gamma Rays
The beam vs omni broadcast is controversial. Earlier, some researchers had hypothethized that GRBs were beamed which meant that the burst was less energetic but woe be unto to he who's in the path. More lately statistics and other analyses indicated that the GRBs are REALLY powerful and not all that "beamed". I don't have uRLs, just imperfect memory. Nobody really knows.