AGN EMISSION ABOVE 20 KEV - THE HARD X-RAY-DETECTION PROBLEM

We have searched the HEAO-4 LED all-sky survey database (13-180 keV) f or a class of AGN that is most likely to emit X-rays at energies of al most-equal-to 50 keV and above, as a basis for further studies with th e Compton Gamma Ray Observatory (CGRO). We have overlayed the survey s ignals of several samples of AGN - quasars, BL Lacs and Seyfert galaxi es - with individual source flux below a significance of 3sigma. The o bjects were selected by their prominence and properties at other wavel engths, and in Einstein observations and the HEAO-A1 survey. We find n o significant signal at hard X-rays from any of the chosen classes of radio- loud QSOs and BL Lacs. We find a signal from Seyfert 1 galaxies up to 80 keV compatible with the canonical energy index alpha = 0.7.