Does the Crab Have a Shell

  title={Does the Crab Have a Shell},
  author={Dale A. Frail and Namir E. Kassim and Tim J. Cornwell and W. M. Goss},
  journal={The Astrophysical Journal},
Abstract : We present deep images of a region around the Crab Nebula made with the VLA, utilizing new imaging and deconvolution algorithms in a search for a faint radio shell. The existence of a high-velocity, hydrogen-rich envelope has been predicted to account for the low total mass and kinetic energy of the observed nebula. No radio emission was detected from an extended source outside the Crab Nebula. Our limits on surface brightness are sufficiently low to rule out the existence of a shell… Expand

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