a radius of 10 km; even for the minimum neutron star radius consistent with reasonable equations of state ($R\sim7$ km), the derived $L_X$ is too high by a factor of 20. Lowering $T$ to $8.5
\times 10^5$K as advocated by Seward et al. (2000) yields self-consistent values for $L_X, R, T$, and $d$, and raises the intrinsic luminosity by $\sim30\%$. Adjusting the distance, and including such effects as non-grey opacity in the neutron star atmosphere and a non-uniform temperature distribution over the surface will also affect the calculated luminosity. For the purpose of a comparison with glitch models (§6), we adopt $T=1.0 \times 10^6$ K.

The integrated luminosity of the whole nebula ($r<52.7^{\prime\prime}$ minus the pulsar) in the $0.1-10$ keV band is $3.5 \times 10^{32} d^{2}_{250}$ erg s$^{-1}$, corresponding to $4.9
\times 10^{-5}$ of the pulsar’s spin down luminosity. This ratio of $L_{neb}/ \dot E$ is significantly lower than that for any other pulsar, and is a major constraint on models for coupling the pulsar wind to the nebula (see §6).

The X-ray pulse profile
=======================

After many unsuccessful searches, Ögelman et al. (1993) were the first to detect X-ray pulsations from the Vela pulsar using the ROSAT PSPC. Their 