Temporal structure of very high energy gamma radiation from PSR 1509 - 58

Further observations of steady, pulsed TeV gamma-rays from PSR 1509 - 58 which confirm an original detection in 1985 are reported. A final chance probability of 1.7 x 10 to the -5th is obtained. Analysis of the data indicates a switching between an on- and an off-state on a time scale of about 10 days. Episodes of pulsed emission lasting between 10 and 100 min are found. The TeV light curve generally shows a broad structure containing three and sometimes four peaks with variations in the relative intensity of the peaks. 26 refs