Comparison Of VSB From BATSE, KONUS And SWIFT

We show the locations of the SWIFT short hard bursts (SHB) with afterglows onthe Galactic map and compare with the very short bursts (VSB) BATSE events. Aswe have pointed out before, there is an excess of events in the Galactic map ofBATSE VSB events. We note, that none of VSB SWIFT era events fall into thiscluster. More SWIFT events are needed to check this claim. We also report a newstudy with KONUS data of the VSB sample with an average energy above 90 keVshowing a clear excess of events below 100 ms duration (T_90) that have largemean energy photons. We suggest that VSB themselves consists of two subclasses:a fraction of events have peculiar distribution properties and have nodetectable counter parts, as might be expected for exotic sources such asPrimordial Black Holes.Comment: 9 pages, 4 figure