Search for discrete sources of 100 TeV gamma radiation

The Chicago Air Shower Array is a large-area ground-based detector designed to observe extensive air showers produced by primary particles with energy ≳ 100 TeV. It operates in coincidence with the underground Michigan Muon Array. Data taken during 1989 are examined for evidence of continuous and pulsed emission from localized regions of the sky. The x-ray sources Cygnus X-3, Hercules X-1, and the Crab Nebula and pulsar are examined for steady and periodic $\gamma$-ray emission. To search for previously unknown compact sources, the background of cosmic rays is estimated over the sky between declinations +5° and +90° and enhancement is sought in small angular bins. There is no evidence for a significant excess from any of these searches, and flux limits are presented as a function of declination and muon content.