Search for Ultra-High Energy Emission from Geminga \\ and Five Unidentified EGRET Sources

Session 33 -- Gamma-Rays and Cosmic Rays
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

[33.09] Search for Ultra-High Energy Emission from Geminga \\ and Five Unidentified EGRET Sources

S.~Biller, P.~Chumney, M.~Harmon, A.~Shoup, G.B.~Yodh (U.C.Irvine), D.E.~Alexandreas (U.C.Irvine, INFN-Padova), G.E.~Allen, C.Y.~Chang, M.L.~Chen, C.~Dion, J.A.~Goodman, T.J.~Haines, M.J.~Stark (U.Maryland), G.M.~Dion (U.Maryland, ICRR-Tokyo), D.~Berley (U.Maryland, NSF), R.L.~Burman, C.M.~Hoffman, D.E.~Nagle, D.M. Schmidt, C. Sinnis, D.D.~Weeks (LANL), W.P.~Zhang (LANL, NASA-GSFC), R.W.~Ellsworth (George Mason U.), M.~Cavalli-Sforza, D.~Coyne, D.~Dorfan, L.~Kelley, S. Klein, R.~Schnee, D.A.~Williams, T.~Yang, (U.C.Santa Cruz), J.-P.~Wu (U.C.Riverside)

Data from the CYGNUS extensive air shower array were searched for continuous ultra-high energy (UHE) gamma radiation from five unidentified EGRET sources and from the Geminga pulsar. No evidence for continuous emission from any of these objects was found. Data in the Geminga source bin were also searched for pulsed emission using the recent EGRET ephemeris (237 ms period). No evidence of a periodic signal was found. The 90\% confidence level upper limit on the continuous gamma-ray flux above 80 TeV for Geminga is $7.9 \times 10^{-14}$ cm$^{-2}$ s$^{-1}$.

Tuesday program listing