We present broadband ( 3 – 78 keV ) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar .
We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power-law in this energy band , spatially resolved spectroscopy of the nebula finds a break at \sim 9 keV in the spectral photon index of the torus structure with a steepening characterized by \Delta \Gamma \sim 0.25 .
We also confirm a previously reported steepening in the pulsed spectrum , and quantify it with a broken power-law with break energy at \sim 12 keV and \Delta \Gamma \sim 0.27 .
We present spectral maps of the inner 100 ^ { \prime \prime } of the remnant and measure the size of the nebula as a function of energy in seven bands .
These results find that the rate of shrinkage with energy of the torus size can be fitted by a power-law with an index of \gamma = 0.094 \pm 0.018 , consistent with the predictions of Kennel and Coroniti ( 1984 ) .
The change in size is more rapid in the NW direction , coinciding with the counter-jet where we find the index to be a factor of two larger . NuSTAR observed the Crab during the latter part of a \gamma -ray flare , but found no increase in flux in the 3 - 78 keV energy band .