The Crab nebula: Linking MeV synchrotron and 50 TeV inverse Compton   photons
  Pulsar wind driven synchrotron nebulae are offering a unique view on the connection of the pulsar wind and the surrounding medium. The Crab nebula is particularly well suited for detailed studies of the different emission regions. As inferred from the observed synchrotron emission extending beyond MeV energies, the Crab is a unique and extreme accelerator. In the framework of the synchrotron/inverse Compton emission model, the same electrons with energies exceeding $10^{15}$ eV that are responsible for the MeV synchrotron emission produce via inverse Compton scattering 10-50 TeV radiation which has recently been observed with the HEGRA system of ground based gamma-ray telescopes. Here we discuss the close relation of the two energy bands covered by INTEGRAL and ground based gamma-ray telescopes. Despite the lack of sufficient spatial resolution in both bands to resolve the emission region, correlation of the flux measurements in the two energy bands would allow to constrain the structure of the emission region. The emission region is expected to be a very compact region (limited by the life-time of the electrons) near the termination shock of the pulsar wind. We extend previous model calculations for the nebula's emission to include an additional compact non-thermal emission region recently detected at mm wavelengths.The overall good agreement of this model with data constrains additional emission processes (ions in the wind, inverse Compton from the unshocked wind) to be of little relevance. 
D. Horns & F.A. Aharonian (Max-Planck Institut f. Kernphysik,   Heidelberg)