A Search for Ultra-High-Energy Gamma-Ray Emission from the Crab Nebula and Pulsar

We have examined 2.4{times}10{sup 9} events recorded by the Chicago Air Shower Array{endash}Michigan Muon Array (CASA-MIA) experiment for evidence of ultra{endash}high-energy ({approx_gt}100TeV) neutral particle and gamma-ray emissions from the Crab Nebula and Pulsar between 1990 March 4 and 1995 October 9. No such emissions have been detected. Over this interval, the 90{percent} confidence level integral flux limits for continuous emission above 141 TeV are 2.08{times}10{sup {minus}14}cm{sup {minus}2}s{sup {minus}1} for any neutral particle (which can produce a detectable air shower) and 9.21{times}10{sup {minus}15}cm{sup {minus}2}s{sup {minus}1} for gamma rays. There is no evidence of transient emission on timescales of 1 day or longer. The 90{percent} confidence level integral flux limit for emission on a single day is conservatively estimated to be 4.40{times}10{sup {minus}12}cm{sup {minus}2}s{sup {minus}1} for any neutral particle and 5.09{times}10{sup {minus}12}cm{sup {minus}2}s{sup {minus}1} for gamma rays. There is no evidence for emission from the pulsar at the radio period on intervals of 1 day or longer. The 2 {sigma} (97.7{percent} confidence) limit on the pulsed flux on the most significant day is 3.29{times}10{sup {minus}12}cm{sup {minus}2}s{sup {minus}1} for any neutral particle with mass less than 21 MeV, and 8.31{times}10{sup {minus}12}cm{sup {minus}2}s{sup {minus}1} for gamma rays. For an interval of 162 sidereal days beginning 1992 March 1, the pulsed flux limit was 2.39{times}10{sup {minus}13}cm{sup {minus}2}s{sup {minus}1} for any neutral particle with mass less than 21 MeV, again above 141 TeV. {copyright} {ital 1997} {ital The American Astronomical Society}