In search of cosmic sources of very high energy gamma rays

Researchers at Potchefstroom are the first to discover a steady cosmic source of very high energy gamma rays. This work permits the study of extremely energetic interactions between elementary particles. Some ways to discriminate between the uninteresting protons and the very interesting gamma rays is to (1) compare the Cherenkov images of proton- and gamma-ray-induced showers, (2) compare the count rate in the direction of the source with the count rate away from the source, and (3) look for a time signature in the data. Little is written about searches for periodicity in data. New but powerful techniques were developed at Potchefstroom which allow the detection of such periodicities even if the radiation pattern of the source is unknown. Development of these techniques led to the discovery of at least two new sources of VHE gamma rays: (1) the x-ray binary system VELA X-1 and (2) the 1600-year-old isolated radio pulsar PSR1509-58