Galactic sources of TeV gamma rays

A ground‐based Cerenkov detector of TeV gamma rays can have a somewhat greater counting rate than the EGRET detector of GeV gamma rays, but with a large background count rate. Using the imaging technique this background can be reduced by orders of magnitude, but so far only one galactic source (the Crab nebula) stands out steadily above noise. At least one other supernova remnant deserves study now in the TeV region. Attention is drawn to the fact that virtually all claimed galactic TeV sources (detected generally by non‐imaging techniques) are episodic, generally seeming to pulsate at neutron‐star spin frequencies, but there are now two or three sources reported to pulsate somewhat faster than the neutron star, suggesting a seat for the acceleration in the accretion disc. Because of the statistics of emission episodes, we need a technique that can deliver longer observations of particular sources to test the reproducibility of some results (e.g. a fast pulsar in Cygnus X‐3).