FRB search techniques have been progressing however, and efforts such as the SUPERB survey are pioneering real-time analysis of vast areas of sky to search for these transients. Their efforts have not gone unrewarded: over the last few years a growing number (3) of FRBs have been spotted in real time and triggered a frenzy of follow-up at all wavelengths.
The sooner we can detect and alert others to these bursts, the more likely we are to discover clues pointing towards their origins, but regardless of how late we uncover FRBs, reobservation of the areas of sky where they occurred may provide information with which we might infer their origins. If FRBs are discovered to repeat for example, it would indicate that their progenitors survived the initial outburst, which would in turn suggest that the pulses are some of the most extreme symbols ever measured from pulsars, or even signatures of extragalactic planets. Non-repetition may suggest that FRBs result from of devastating cataclysmic events - possibly the signatures of some of the most violent events in the universe - for example the collision of binary neutron stars or the births of black holes. Recent contradictory observations suggest that either, or maybe even both may be the case, and that we have still not quite grasped the bigger picture. Behind our fragmentary observations may hide a much more diverse population of transient radio signals waiting to be uncovered.
The current difficulty with definitively confirming FRB origins as extragalactic is due disadvantages of the apparatus used to detect them. Single telescopes, for example the Parkes telescope (Australia), have extremely large fields of view (greater than ten arcminutes), which could hold hundreds or even thousands of individual galaxies; within those fields the exact location of any detected FRB is not well known. Thus it can be extremely hard to pin down a host galaxy for a burst, and measure its redshift. One way this may be achieved is via a technique known as radio interferometry, and here at Manchester we are hard at work devising a way for a series of UK based radio telescopes collectively known as the eMERLIN interferometer to confirm or refute the extragalactic origin of FRBs once and for all.