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The results of a search for TeV emission from AGN's and unidentified high latitude EGRET sources using the Whipple Observatory High Resolution atmospheric Cherenkov Camera is reported. The observations were made over the epoch 1992-94. The threshold energy is 0.25 TeV. Of the 35 objects studied (12 of which had been detected at GeV energies by EGRET), only Markarian 421 gave a significant signal. Markarian 421 is the closest AGN seen by EGRET. The failure to detect emission from other stronger, but more distant, AGN's has led to speculation that the intergalactic infrared background is responsible for significant absorption causing photon-photon pair production.
Supported in part by the U.S.~Dept.~of Energy
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