  A large fraction of the recently discovered Galactic Very High Energy (VHE)
source population remains unidentified to date. VHE gamma-ray emission traces
high energy particles in these sources, but for example in case of hadronic
processes also the gas density at the emission site. Moreover, the particles
have sufficiently long lifetimes to be able to escape from their acceleration
sites. Therefore, the gamma-ray sources or at least the areas of maximum
surface brightness are in many cases spatially offset from the actual
accelerators. A promising way to identify the objects in which the particles
are accelerated seems to be to search for emission signatures of the
acceleration process (like emission from shock-heated plasma). Also the
particles themselves (through primary or secondary synchrotron emission) can be
traced in lower wavebands. Those signatures are best visible in the X-ray band,
and current X-ray observatories are well suited to conduct such follow-up
observations. Some aspects of the current status of these investigations are
reviewed.
