Astronomy Colloquium

Several reports of intense radio pulses---lasting only milliseconds--have been fuelling a heated debate as to the origin of this emission. Until recently, it was widely hypothesized that such bursts were Earth-local, but a growing body of evidence is demonstrating that some may be arriving from extragalactic sources at redshifts up to z~2. As an extragalactic population, these bursts would be unprecedented probes of extragalactic baryons and hitherto unidentified physical processes.

I will outline the entertaining state of radio burst research, and describe the emerging evidence that we are seeing several sub-populations that range from local to cosmic origins. I will discuss potential progenitors of extragalactic "Fast Radio Bursts", and describe ongoing work to identify where they are, and what they are.