NUMERICAL SIMULATIONS OF THE JET IN THE CRAB-NEBULA

Observations and earlier models of the 'jet' in the Crab nebula are reviewed, and a new model, in which the 'jet' is formed by material from the supernova remnant propagating up the interior of a cooled star trail left by the progenitor, is described. This model is similar to a previous model for the 'jet' by Blandford et al., but differs in that the 'jet' lies in the plane of the sky, and the Crab's progenitor moves supersonically rather than subsonically through the interstellar medium. Numerical simulations indicate that the model offers a successful description of the structure of the 'jet'. In the light of these simulations we conclude that the nebula is situated within the warm component of the interstellar medium, and that its proposed outer halo does not exist.