The high energy budget allocations in shocks and gamma ray bursts

The statistical distribution of energies among particles responsible for long gamma-ray burst (GRB) emission is analyzed in light of recent results of the Fermi Observatory. The all-sky flux, F_γ , recorded by the Gamma-Ray Burst Monitor (GBM) is shown, despite its larger energy range, to be not significantly larger than that reported by the Burst and Transient Explorer, suggesting a relatively small flux in the 3-30MeV energy range. The present-day energy input rate in γ-rays recorded by the GBM from long GRBs is found, assuming star formation rates in the literature, to be Ẇ(0) = 0.5F _γH/c = 5×10⁴² ergMpc^-3 yr ^-1. The Large Area Telescope fluence, when observed, is about 5%-10% per decade of the total, in good agreement with the predictions of saturated, nonlinear shock acceleration. The high-energy component of long GRBs, as measured by Fermi, is found to contain only ~10^-2.5 of the energy needed to produce ultrahigh-energy cosmic rays (UHECRs) above 4 EeV, assuming the latter to be extragalactic, when various numerical factors are carefully included, if the cosmic-ray source spectrum has a spectral index of -2. The observed γ -ray fraction of the required UHECR energy is even smaller if the source spectrum is softer than E ^-2. The AMANDA II limits rule out such a GRB origin for UHECRs if much more than 10^-2 of the cosmic-ray energy goes into neutrinos that are within, and simultaneous with, the γ -ray beam. It is suggested that " orphan" neutrinos out of the γ -ray beam might be identifiable via orphan afterglow or other wide angle signatures of GRBs in lieu of coincidence with prompt γ-rays, and it is recommended that feasible single neutrino trigger criteria be established to search for such coincidences.