Yet Another Model of Gamma‐Ray Bursts

Sari and Piran have demonstrated that the time structure of gamma-ray burstsmust reflect the time structure of their energy release. A model whichsatisfies this condition uses the electrodynamic emission of energy by themagnetized rotating ring of dense matter left by neutron star coalescence; GRBare essentially fast, high field, differentially rotating pulsars. The energydensities are large enough that the power appears as an outflowing equilibriumpair plasma, which produces the burst by baryon entrainment and subsequentinternal shocks. I estimate the magnetic field and characteristic time scalefor its rearrangement, which determines the observed time structure of theburst. There may be quasi-periodic oscillations at the rotational frequencies,which are predicted to range up to 5770 Hz (in a local frame). This model isone of a general class of electrodynamic accretion models which includes theBlandford and Lovelace model of AGN, and which can also be applied to blackhole X-ray sources of stellar mass. The apparent efficiency of nonthermalparticle acceleration is predicted to be 10--50%, but higher values arepossible if the underlying accretion flow is super-Eddington. Applications tohigh energy gamma-ray observations of AGN are briefly discussed.Comment: 21pp, latex, uses aaspp4.st