  Vela X is a large, 3x2 degrees, radio-emitting pulsar wind nebula (PWN)
powered by the Vela pulsar in the Vela supernova remnant. Using four Suzaku/XIS
observations pointed just outside Vela X, we find hard X-ray emission extending
throughout the fields of view. The hard X-ray spectra are well represented by a
power-law. The photon index is measured to be constant at Gamma~2.4, similar to
that of the southern outer part of Vela X. The power-law flux decreases with
increasing distance from the pulsar. These properties lead us to propose that
the hard X-ray emission is associated with the Vela PWN. The larger X-ray
extension found in this work strongly suggests that distinct populations
relativistic electrons form the X-ray PWN and Vela X, as was recently inferred
from multiwavelength spectral modeling of Vela X.
