A SEARCH FOR ULTRA-HIGH-ENERGY GAMMA-RAY EMISSION FROM THE CRAB-NEBULA AND PULSAR

We have examined 2.4 x 10(9) events recorded by the Chicago Air Shower Array-Michigan Muon Array (CASA-MIA) experiment for evidence of ultra -high-energy (greater than or similar to 100 TeV) neutral particle and gamma-ray emissions from the Crab Nebula and Pulsar between 1990 Marc h 4 and 1995 October 9. No such emissions have been detected. Over thi s interval, the 90% confidence level integral flux limits for continuo us emission above 141 TeV are 2.08 x 10(-14) cm(-2) s(-1) for any neut ral particle (which can produce a detectable air shower) and 9.21 x 10 (-15) cm(-2) s(-1) for gamma rays. There is no evidence of transient e mission on timescales of 1 day or longer. The 90% confidence level int egral flux limit for emission on a single day is conservatively estima ted to be 4.40 x 10(-12) cm(-2) s(-1) for any neutral particle and 5.0 9 x 10(-12) cm(-2) s(-1) for gamma rays. There is no evidence for emis sion from the pulsar at the radio period on intervals of 1 day or long er. The 2 sigma (97.7% confidence) limit on the pulsed flux on the mos t significant day is 3.29 x 10(-12) cm(-2) s(-1) for any neutral parti cle with mass less than 21 MeV, and 8.31 x 10(-12) cm(-2) s(-1) for ga mma rays. For an interval of 162 sidereal days beginning 1992 March 1, the pulsed flux limit was 2.39 x 10(-13) cm(-2) s(-1) for any neutral particle with mass less than 21 MeV, again above 141 TeV.