The Magnetic Field of the Crab Nebula and the Nature of Its ``Jet''

The results of multifrequency, polarimetric VLA observations of the Crab Nebula are presented, which make it possible to correct for Faraday rotation and map the projected magnetic field with 1.8 arcsec resolution. It is found that, along most of the periphery where high sensitivity detects the magnetic field orientation for the first time, the field is aligned radially with an apparent high degree of order. The observed Faraday rotation is constant over most of the Crab and has the same value over the 'jet', suggesting that, apart from certain filaments and other small areas, it is of interstellar origin. It is concluded that most likely the jet is the result of a high-velocity beam formed inside the nebula.