The extended hard X-ray emission from the Vela Plerion

We present the results of a broad band (3-200 keV) spectral analysis of BeppoSAX and XMM-Newton observations oftheVelaplerion. The hard X-ray (>15 keV) emission is found to be extended over a region of 12'-15' radius, corresponding to a size of about 1.0-1.3 pc for a source distance of 290 pc. A single power law does not give an acceptable fit while a broken power law or a log-parabolic law nicely fit the data. The former spectral model has the photon index Γ 1 = 1.66 ± 0.01 for energies lower than the break value equal to 12.5 keV and the index Γ 2 = 2.01 ± 0.05 up to about 200 keV. The total X-ray luminosity oftheVelaplerion is L X = 5.5 x 10 33 erg s -1 , which implies a conversion factor of the spin-down power of ∼10 -3 .