Search for Emission of Ultra High Energy\\ Radiation from Active Galactic Nuclei

Session 12 -- High Energy Observations of AGNs
Oral presentation, Monday, 10:30-12:00, Zellerbach Auditorium Room

[12.08] Search for Emission of Ultra High Energy\\ Radiation from Active Galactic Nuclei

G.B.~Yodh, S.~Biller, P.~Chumney, M.~Harmon, A.~Shoup (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)

A search for emission of ultra-high energy gamma radiation from 13 active galactic nuclei that were detected by EGRET, using the CYGNUS extensive air-shower array, is described. The data set spans the period 1986 April 2 to 1993 January 1. The data set has been searched for continuous emission, emission on the time scale of one week, and for emission on the time scale of one day. No evidence for emission from any of the AGN on any of the time scales examined was found. The $90\%$ C.L. upper limit to the continuous flux from Mrk 421 above 50 TeV is $7.5\times 10^{-14} \; cm^{-2} s^{-1}$.

Monday program listing