SEARCH FOR X-RAY PULSATIONS FROM THE GAMMA-RAY SOURCE 3EG J1809-2328

The error box of the highenergy gammaray source 3EG J18092328 contains anXray and radio synchrotron nebula emerging from a point Xray source that isundoubtedly a radioquiet pulsar. Since the gammarays from 3EG J18092328 arevariable on time scales of months to years, they may be of a qualitativelydifferent origin from the usual magnetospheric emission from rotationpoweredpulsars. We propose to discover the pulsations in Xrays in order to evaluatewhether the gammarays can be powered by the spindown luminosity of the pulsar.The resulting pulse ephemeris will also be used in conjunction with future GLASTdata to determine what fraction of the gammarays are pulsed, and what remainingfraction can be powered by diffuse mechanisms involving pulsar wind nebulae. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]