Stringent upper limit on the number density of primordial black holes seems to rule out the possibility of their discovery in the near future. Contrary to this widely accepted opinion, we show that, when the black-hole temperature exceeds 10 GeV, the charged particle outflow from a black hole forms a plasma and the magnetohydrodynamical regime of expansion can be realized. In this case, the kinetic energy of particles can be converted into the 0.1-1 MeV gamma-rays due to the synchrotron radiation and electromagnetic cascade in the close-to-equipartition turbulent magnetic field, producing a burst of duration <= 1000 s. We show that some of the gamma-ray bursts detected by BATSE can be associated with evaporating black holes.
19th Texas Symposium on Relativistic Astrophysics and Cosmology
- Pub Date:
- December 1998