THE COMPTON MIRROR IN NGC-4151

We show that the sharp cutoff in the hard X-ray spectrum of NGC 4151, unusual for Seyfert 1 galaxies, can be reconciled with the average Sey fert 1 spectrum if we assume that the central source is completely hid den from our line of sight by the thick part of the accretion disk or by the broad emission-line clouds. The observed X-ray radiation is pro duced by scattering of the Seyfert 1 type spectrum in the higher, cool er parts of the accretion disk corona, or in a wind. A sharp cutoff ap pears as a result of the Compton recoil effect. This model naturally e xplains a discrepancy regarding the inclination of the central source, inferred to be low (face-on) from observations of the iron K alpha em ission line, but inferred to be high on the basis of optical and UV ob servations.