  The observational progress in the $\gamma$-ray astronomy in the last few
years has led to the discovery of more than a thousand sources at GeV energies
and more than a hundred sources at TeV energies. A few different classes of
compact objects in the Galaxy have been established. They show many unexpected
features at high energies the physics of which remains mainly unknown. At
present it is clear that detailed investigation of these new phenomena can be
performed only with the technical equipment which offer an order of magnitude
better sensitivity, and a few times better energy, angular and time resolution
in the broad energy range staring from a few tens of GeV up to a few hundreds
TeV. Such facilities can be realized by the next generation of instruments such
as the planned Cherenkov Telescope Array (CTA).
  The aim of this report is to summarize up to date observational results on
the compact galactic sources in the GeV-TeV $\gamma$-ray energy range, discuss
their theoretical implications, and indicate which hypothesis considered at
present might be verified with the next generation of telescopes. We point out
which of the observational features of the $\gamma$-ray sources are important
to investigate with special care with the planned CTA in order to put a new
light on physical processes involved. Their knowledge should finally allow us
to answer the question on the origin of energetic particles in our Galaxy.
