
We can only say that they are beyond about 25 AU, due to the low
accuracy of position determination by single detectors.


It may be a NEW Physics problem (i.e. a problem involving new
physics).  However, the data is not good enough to rule out the >100
models which use old physics.  New physics is a big step, and is only
tolerated when there is no alternative.  For example , the Dark Matter
Problem (there's more to the universe than meets the eye) is a question
of comparable mystery to GRBs, but we have much better data regarding
it.  Theoreticians postulate new particles all the time to explain it,
but no one will actually believe that these particles are real until an
experimentalist (or several) detects them in the lab.
