ar X iv : a st ro - p h / 02 02 26 5 v 1 1 3 Fe b 20 02 To the Lighthouse

The extreme hypothesis that essentially all types of ultrarelativistic outflow – specifically AGN jets, pulsar wind nebulae and GRB –are electromagnetic, rather than gas dynamical, phenomena is considered. It is suggested that the observed emission is generated in regions of high current density where global instabilities drive a turbulence spectrum that is ultimately responsible for the particle acceleration and the synchrotron and inverse Compton emission. Electromagnetic flows are naturally anisotropic and self-collimating. The relativistic force-free description of these flows, which is simpler than the relativistic MHD description, is explained. It is suggested that the magnetic field associated with AGN jets and GRB is quite extensively distributed in latitude, without increasing the overall energy in the flow. The direct extraction of spin energy from a black hole is re-examined and an electromagnetic model of GRB explosions is developed. It is also suggested that the GRB “lighthouse” be identified with accretion-induced collapse of a neutron star to form a black hole in a binary system.