A SURVEY OF EGRET SOURCES FOR PULSED RADIO-EMISSION

We have made deep searches for pulsed radio signals toward gamma-ray s ources detected by the EGRET instrument of the Compton Gamma Ray Obser vatory. Our observations targeted 19 sources in the second EGRET sourc e catalog (2EG), primarily sources along the Galactic plane without id entified counterparts. Our observations also covered eight locations l isted in earlier catalogs but not in 2EG. Data were collected at 370, 770, and 1390 MHz with the Green Bank 140 foot telescope. Flux density limits were 0.5-1.0 mJy for slow pulsars, with somewhat less sensitiv ity at short pulse periods. We discovered no new pulsars. We detected two previously known pulsars, PSR B0611+22 and PSR B1758-23, which are apparently not associated with cataloged gamma-ray sources. Our nonde tection of radio pulsars associated with the EGRET sources weakly cons trains models of the gamma-ray source population. In particular, we ru le out a model in which all the Galactic gamma-ray sources are pulsars with a 50% beaming fraction.