1994A&A...290..364R

In the frame of the two-fluid model of extragalactic radio sources, the properties of extragalactic γ-ray bursters can be explained by the emission of a precessing relativistic e^± beam whose bulk Lorentz factor is γ_b≃10. The γ-ray emission of the ejected e^± component has a non-thermal origin and is due to the e^± annihilations and the inverse Compton losses. Due to the relativistic motion of the e^± component, its emission is strongly anisotropic. When several peaks are observed, the typical time scale between the peaks is of a few seconds and it corresponds to a perturbation period of the beam of about P_o≃100s. This high frequency perturbation corresponds to the rotation frequency of a compact object turning at almost 3 Schwarzschild radii around a central black hole of mass 10⁵M_☉≤M≤10⁶M_☉. The rotating compact object perturbs the accretion disk around the black hole and the frozen magnetic field of the jet. It induces a precession of the beam and an e^± component is ejected relativistically in the precessing beam producing a γ-ray emission which appears to be pulsating for the observer. Due to the rotation of the compact object the system emits gravitational waves together with the γ-ray emission. Finally, γ-ray bursters are associated with distant normal galaxies and after few months we expect an anisotropic radio emission whose flux density is S_ν≤0.15mJy if the redshift of the galaxy is z≥0.2.