Limits on cosmic radio bursts with microsecond time scales

Abstract

IT has been suggested¹ that black holes of mass ≤10¹⁵ g evaporate in ∼10¹⁰ yr, ultimately annihilating into a burst of energetic photons and particles. This explosion would produce γ-rays directly, and a radio pulse with a characteristic frequency of ∼3 GHz and an energy of ∼10³² erg may also be generated². It has been shown^2–4 that such a radio burst would be far more easily detected than the corresponding γ-ray burst. Estimates of the energy in the radio burst are uncertain by many orders of magnitude, and it is, of course, not known whether any primordial black holes exist at all; however, the implications of a detection would be enormous for quantum and gravitational physics.