The Crab Nebula's Moving Wisps in Radio

Abstract

We present three high resolution radio images of the Crab nebula, taken in 1998.6, 1998.8 and 2000.1 with the VLA. These are the best radio images of the Crab to date. We show that, near the pulsar, there are significant changes between our three observing epochs. These changes have an elliptical geometry very similar to that of the optical wisps. One radio wisp in particular can be unambiguously identified between two of our observing epochs, and moves outward with an apparent velocity of ~0.24. The similarity in both morphology and behavior of the present radio wisps to the optical wisps suggests that they are associated. This implies that the radio wisps, like the optical ones, are likely manifestations of the shock in the Crab pulsar's wind. This suggests that the radio emitting electrons are accelerated in the same region as the ones responsible for the optical to X-ray emission, contrary to most current models.