LOW-FREQUENCY SPECTRA OF GAMMA-RAY BURSTS

Particles with energies below the mean energy E0 in relativistic shocked plasmas should assume an equilibrium energy distribution. This leads to a synchrotron spectrum F(nu) proportional-to nu1/3 up to approximately the critical frequency nu0 of an electron with the energy E0. Application to gamma-ray bursts (GRBs) implies that a burst with 10(-5) ergs cm-2 s-1 of soft gamma rays and hnu0 = 300 keV should simultaneously be about 18th magnitude in visible light and a few muJy at 1 GHz (less if self-absorbed); the low-frequency intensities peak later at higher values.