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abstract: |
    We present high-resolution  X-ray observations of , the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations separated by one month to search for changes in the pulsar and its environment following an extreme glitch in its rotation frequency. We find a well-resolved nebula with a toroidal morphology remarkably similar to that observed in the Crab Nebula, along with an axial Crab-like jet. Between the two observations, taken $\sim3\times10^5$s and $\sim3\times10^6$s after the glitch, the flux from the pulsar is found to be steady to within $0.75
    \%$; the $3 \sigma$ limit on the fractional increase in the pulsar’s X-ray flux is $\simlt 10^{-5}$ of the inferred glitch energy. We use this limit to constrain parameters of glitch models and neutron star structure. We do find a significant increase in the flux of the nebula’s outer arc; if associated with the glitch, the inferred propagation velocity is $\simgt0.7c$, similar to that seen in the brightening of the Crab Nebula wisps.

    We propose an explanation for the X-ray structure of the Vela synchrotron nebula based on a model originally developed for the Crab Nebula. In this model, the bright X-ray arcs are the 