Search for pulsed TeV gamma-ray emission from the Crab pulsar

We present the results of a search for pulsed TeV emission from the Crab pu lsar using the Whipple Observatory's 10-m gamma-ray telescope. The directio n of the Crab pulsar was observed for a total of 73.4 hr between 1994 Novem ber and 1997 March. During this period the Whipple 10 m telescope was opera ted at its lowest energy threshold to date. Spectral analysis techniques we re applied to search for the presence of a gamma-ray signal from the Crab p ulsar over the energy band 250 GeV to 4 TeV. We do not see any evidence of the 33 ms pulsations present in other energy bands from the Crab pulsar. Th e 99.9% confidence level upper limit for pulsed emission above 250 GeV is d erived to be 4.8 x 10(-12) cm(-2) s(-1) or less than 3% of the steady flux from the Crab Nebula. These results imply a sharp cutoff of the power-law s pectrum seen by the EGRET instrument on the Compton Gamma-Ray Observatory. If the cutoff is exponential, it must begin at 60 GeV or lower to accommoda te these upper limits.